EDWIN CHAPIN STARKS il 49, Chalcinus rotundus (Schomburgk).
One specimen was taken by Dr. Baker and Mr. Mann at the mouth of the Rio Madeira. Comparing it with a specimen collected by Dr. Eigenmann at British Guiana it differs only in having no dark pigment anywhere on the fins or body.
50. Chalcinus elongatus Giinther.
A number of small specimens up to 8 inches in length were taken at Para. The length of the pectoral is usually equal to half of the distance between the snout and the dorsal, but it varies from this to half of the distance between the snout and the last dorsal ray. It reaches to the middle of the ventral, which reaches half way from its base to the anal. The front of the anal is under the last dorsal ray or a little behind. ‘The pectorals are sometimes colorless or sometimes dark with fine black points. The adipose dorsal is over the last anal ray and coterminous with it, or often the latter projects a trifle farther back.
51. Piabucus dentatus Koelreuter.
Three specimens, the largest 6 inches in length, were obtained at Para. They agree very well with the description published by Dr. Eigenmann (F. W. Fish. of Brit. Guiana, p. 316) except in depth of body. It is there stated to be 3.6 of the length. Giinther (Cat. V., p. 343) gives the depth as one-fifth or one-sixth of the total length, including the caudal, and the picture published by Bloch (Ausl. Fische, p. 382) agrees with this. In my specimens the depth is from 4% to 434 in the length to the caudal base, or 5% to 534 with the caudal. It is possible that Dr. Eigenmann’s description should read 4.6 rather than 3.6.
52. Pygopristis gibbosus Starks, new species.
Plate 3.
Though this species was found to be one of the most common of the forms related to Serrasalmo in the market at Para it seems to have remained undescribed, for it has been referred to Pygopristis denticulatus. The type of Pygopristis denticulatus came from British Guiana, and as the specimen with which I compare this species was collected by Dr. Eigenmann at Lama Stop-off, British Guiana, there is every reason to suppose that it is a representative of that species.
The depth in front of the dorsal is contained in the length 1% times, or sometimes a trifle less. In P. denticulatus it is 134 times (though Dr. Eigenmann reports 1.66). The outline of the body is much more angu-
18 FISHES FROM BRAZIL lated and the curve from the dorsal to the snout much more pronounced than in the Guiana species, being more convex at the nape and concave above the eyes. The head is contained from 3% to 336 times in the length. The eye is contained from 3% to 334 times in the head. Five trilobed teeth are at each side of the upper jaw, and 7 at each side of the lower. They are about as distinct, and sharp, and as well developed posteriorly on the mandible as anteriorly, while in P. denticulatus they are lower, blunter, and less projecting posteriorly. ‘The mandible is rather slender; its depth in front is less than half of the diameter of the eye, and is contained 3 times in its own length. In the other species the mandible is very heavy, its depth being equal to three-quarters of the eye, or half of its own length. There are 33 ventral scutes besides a paired one in front of the vent and another behind it, but there are none at the side of the.vent as in P. denticulatus, where there are four at each side posterior to the median ones. There are 15 or 16 dorsal rays, and 32 or 33 anal rays. In other species there are 19 dorsal rays and 35 anal rays. The distance from the dorsal to the adipose dorsal is scarcely shorter than the base of the dorsal, while in P. denticulatus it is not over half as long as the dorsal base. ‘The first anal rays are a little produced beyond the others. The length of the pectoral is contained 1% times in the head; that of the ventral 2 times. The pectoral reaches to above the ventral base, and the ventral to the last unpaired ventral scute. The scales are larger than in the other species, there being 71 tubes in the lateral line, 82 cross series, and about 32 vertically from the lateral line to the front of the dorsal. ‘The scales are rather uneven and difficult to count crosswise, but the difference in size when the scales above the lateral line are directly compared is very striking between the two species, being much finer in P. denticulatus.
The specimen at hand of P. denticulatus, and those described by Dr. Eigenmann, are uniform in color, without spots or a dark caudal margin. In alcohol this species is slate-blue above, silvery below and on the side, and the fins yellow at the base. Over the back and upper part of the side are scattered dark blue spots as large as the pupil and smaller. A dusky blotch is just below the anterior part of the lateral line. The caudal is edged with black.
The type is 6 inches in length, and several cotypes are as large and others slightly smaller.
53. Pygocentrus piraya (Cuvier).
One small specimen was taken at Para. The side is closely covered with dusky spots and the posterior edges of the vertical fins are dark.
EDWIN CHAPIN STARKS 19 54. Serrasalmo spilopleura Kner, A fine specimen of this species was taken by Mr. Mann and Dr. Baker at the mouth of the Madeira River.
55. Metynnis hypsauchen (Miiller and Troschel).
A single small specimen was taken at Para.
56. Metynnis maculatus (Kner).
One specimen was taken at Lake Papary and two at Lake Extremoz. One of the specimens from the last locality has the anal slightly convex and angulated in front, as in the picture accompanying the original description. The other has it more rounded in front and produced at a rounded angle at the anterior third; probably the mark of the male. It also has the spots larger and more definite than in the others. A much darker spot is present in all of them above the anterior end of the lateral line. 57. Myleus parma (Giinther).
Four specimens 6 inches long and one 11 inches, taken in the market at Para. The large one has the middle anal rays produced (male), and the procumbent predorsal spine is scarcely evident. The depth (in the smaller ones) is contained 1%4 times in the length, and the head 4 times. The back is highest at the front of the dorsal, and the ventral outline deepest at the anal, so that the cross axis of the body is oblique. The anal lobe is a trifle longer than the head, and longer than the anterior dorsal rays. The pectoral does not reach to opposite the ventral, which reaches half way, or a little more, from its base to the anal. There are 36 to 38 ventral scutes. The front lobe of the anal is black, and all of the ventral fins are margined with black behind.
58. Mylosoma aureum (Spix).
Three specimens were taken at the mouth of the Madeira River by Dr. Baker and Mr. Mann. ‘The depth is from 1% to 1% in the length to the caudal base. The anal is angulated behind the posterior third, as in the drawing published by Spix. There are 43 or 44 ventral scutes, with 4 or 5 paired ones surrounding the vent. One specimen has 49 scutes, all of them simple and running at one side of the vent. In this it is apparently. abnormal.
59. Mylosoma albiscopus (Cope).
Two specimens taken at Para seem to be referable to this species. The anal is less angulated than in Wylosoma aureum but more evenly rounded,
20 FISHES FROM BRAZIL as in Dr. Cope’s drawing of the type. There are from 47 to 50 simple scutes along the median ventral line, and from 7 to 9 pairs are crowded in around the vent.
60. Mylosoma herniarius (Cope).
Two specimens were collected by Mr. Mann and Dr. Baker just below the mouth of the Madeira River in the Amazon. They are slightly less deep than the picture published by Mr. Fowler (Proc. Phil. Acad. Sci. 1906, p. 477, fig. 56), which has the depth equal to the distance from the snout to the adipose dorsal. In these specimens the depth is equal to the same distance, less 34 the diameter of the eye. The sigmoid curve of the ventral outline is scarcely so pronounced. ‘The anal is covered with scales (M/ylosoma) and on one of the specimens it is angulated posteriorly, as it usually is in M/. aureum, while in the other it is more evenly rounded as in Mr. Fowler’s drawing. ‘The scutes along the ventral ridge number 40, and there are none surrounding the vent.
61. Raphiodon vulpinus Spix.
Several specimens, a foot in length, were collected at Para. The depth of the body is equal to the length of the head, or is contained from 5'%4 to 5% times in the length to the caudal. The eye is contained from 4% to 5 times in the head, and the maxillary 1% times. The cheek is almost entirely covered by the expanded suborbitals. The adipose eyelid has a vertical elongate opening, as in some of the herring-like fishes. The pectoral is a trifle shorter than the anal base, or one-fourth of the length to the caudal. The front of the dorsal is a little behind that of the anal. The caudal is not rounded, as in the picture published by Spix (Pisc. Bras. tab. 26), but is angulated at the tips of the outer rays and double lunate behind, with the middle one or two rays produced considerably beyond the rest of the fin and carrying the lateral line to their tips. The ventrals are in front of the anal a distance equal to the combined length of the snout and the eye.
62. Hydrolycus pectoralis (Giinther).
A couple of specimens, 8 inches long, were taken by Dr. Baker and Mr. Mann in the Amazon River near the mouth of the Madeira River. The body is much deeper than the length of the head, and is contained 31% times in the length to the caudal; the head, without the projecting jaw, 4% times. The pectoral is scarcely as long as described for the type. In one specimen it scarcely extends to the front of the dorsal; in the other it extends just to, though its length as contained in the entire
EDWIN CHAPIN STARKS 21 length is the same (about 3 times). The anal has from 45 to 47 rays, and its base is contained from 334 to 4 times in the length. ‘The caudal is rounded and the middle rays are not produced with the lateral line. The ventrals are a little more than half as long as the head. ‘The anal and caudal are very closely covered with scales. The scales on the body are slightly ctenoid. A large black spot is present on the shoulder girdle above, a small one on the base of the lower pectoral ray, and one on the adipose dorsal.
63. Hydrocynus cuvieri (Agassiz).
This species is not uncommon in the market at Para, where a number of specimens were collected. As our steamer entered the Rio Para, numbers of what appeared to be this form could be seen darting swiftly over the surface of the stream, with the greater part of their bodies out of the water. 64. Hoplias malabaricus Bloch.
This speciés was taken at Cedro Dam, near the town of Quixada, at Ceara Mirim, at Lake Extremoz and at Lake Papary.
65. Hoplerythrinus uniteniatus (Spix).
One specimen was found in the market at Para. I may here call attention to an evident mistake in Dr. Eigenmann’s key to the family Characide (Freshwater Fishes of British Guiana, p. 258). For the above genus and for Erythrinus the walls of the anterior portion of the air-bladder are said to be cellular. In our representatives of this genera it is the second chamber of the air-bladder, the part behind the pneumatic duct, that is cellular. The walls of the anterior chamber and the posterior part of the posterior chamber are simple in structure.
FamMity GYMNOTID.
66. Sternarchus macrolepis Steindachner.
A few specimens were taken at Para. The teeth in the upper jaw are extremely easily lost, and in about half of the specimens at hand they are not to be detected. There is considerable variation in the length and slenderness of the tail and in the position of the vent. 67. Sternarchus albifrons (Linnzus).
A single specimen was found in the market at Para. It has 15 scales between the lateral line and the median line of the back. The head is contained 6% times in the length, and 1% times in the greatest depth.
22. FISHES FROM BRAZIL The angle of the mouth is under the posterior edge of the eye. The snout is contained 3 times in the length of the head, and is equal in length to the longest anal rays. The anal has 152 rays, and its posterior end is distant from the caudal a distance equal to the length of the caudal. The head is slate-color and darker than the rest of the body. On its upper surface is a white, rectangular, longitudinal spot, and from it a thin, light, broken line runs posteriorly along the back. An abrupt white band crosses the body above the posterior part of the anal fin, involving the latter, and a second one crosses the base of the caudal fin and caudal peduncle. The tip of the caudal fin is white. The fins are otherwise jet black. 68. Sternarchella sima Starks, new species.
Plate 4.
The ventral outline of the head and body is more strongly curved than the dorsal. The greatest depth of the body is 7 in the length. The head is small, with its dorsal contour abruptly rounded at the snout, and its ventral contour slightly and evenly curved to the tip of the mandible; its length is contained from 8 to 8% times in the length of the body. The mouth is very small; its gape is more transverse than lateral, nearly straight in front and abruptly curved down at the end of the maxillary on the side. The maxillary reaches to under the very inconspicuous posterior nostril. Small, sharp, movable teeth are present in several series on both jaws. ‘The eyes are small and the thick skin that covers them is continuous with the side of the head, so that their extent is difficult to appreciate. Their diameter is contained 8 times in the length of the head, 2 times in the snout, and 2 times in the interorbital space. At the isthmus is a deep longitudinal groove, at the middle of which the vent is placed a little nearer to a vertical line from the preopercle than one from the eye.
The scales are rather large and thin. There are from 75 to 80 tubes in the lateral line. Over an area extending above the base of the anal rays, and about equal in width to the length of the rays (the area of the interhaemal rays) the scales are abruptly smaller. There are 8 or 9 scales between the lateral line and the scaleless- area of the back at the widest part of the body. The anal begins below the base of the pectoral or very slightly in front of it, and ends a distance from the caudal base nearly equal to the length of the head. It contains 193 rays, the longest of which are a trifle under half of the length of the head. The pectoral is contained 1%% in the head, and has 14 or 15 rays. The length of the caudal is equal to the diameter of the eye.
EDWIN CHAPIN STARKS 23 In life the culor was flesh-color, with the back slightly darker with slaty brown. In alcohol the only pigment is a dusky brown narrow band along the back.
This species may be known from other members of its genus by its having a blunt, rounded snout overhanging a small mouth. Four specimens were taken at Para, all of them about 6 inches in length.
69. Sternarchogiton natterei (Steindachner).
A single small specimen was collected by Dr. Baker and Mr. Mann at the mouth of the Madeira River.
70. Sternarchorhamphus mulleri (Steindachner).
Many specimens of this species were taken at the market at Para. Among them there is a very great variation in the caudal and fin. In many of them the peduncle is nearly twice as long as the head and tapers almost to a point. Its narrowest part is scarcely wider than the very small eye, and the caudal fin is only a trifle wider. In others it is less than the length of the head and tapers more rapidly to a width similar to the first ones. In one specimen it is no longer than the snout and scarcely tapers at all, being three or four times as wide as the narrowest ones, or equal to onefourth of the length of the snout, while the fin is correspondingly large. One specimen has the peduncle very wide and short, and the fin very diminutive as usual. These specimens do not otherwise differ from each other except in the position of the vent, and this variation has no correlation with the caudal variation. The vent may vary from a position a trifle behind the eye to one considerably in front of it.
These specimens are all colorless in alcohol except a slight tinge of orange-yellow on the fins and a slight dusky tinge on the back. One specimen, however, differs in being a rather dark slaty-brown, almost uniform, but slightly darker above; about the opercular region are blue shades; the fins are bright orange, growing yellow toward the tips of the rays, with the tips dusky, or on the pectoral, nearly black.
71. Sternarchorhynchus curvirostris (Boulenger).
This species is common at Para, though it has not been before recorded from the lower Amazon.
72. Sternarchorhynchus oxyrhynchus (Miiller and Troschel). A small specimen was taken by Dr. Baker and Mr. Mann about 400 miles above the mouth of the Rio Madeira.
24 FISHES FROM BRAZIL 73. Rhamphichthys rostratus (Linnezus).
One specimen was collected at Para. The postorbital part of the head is contained 1% times in the length of the snout.
74. Rhamphichthys reinhardtii Kaup.
Many specimens of this common species were seen in the market, though on account of their large size only 5 were collected. I follow Doctor Eigenmann in recognizing this species, while believing with him that it is probably a long-snouted variation of &. rostratus. Though there is little difference between these species, except the rather extraordinary one of the length of the snout, it seems better to keep them separate until intermediate variations are reported. In the specimens before me the body is more slender and more gradually tapering backward than in the single specimen of Ahamphichthys rostratus, but as this character shows considerable variation it is less remarkable.
The postorbital part of the head, measured obliquely to the middle of the gill opening, is contained in the length of the snout from 1% to 134 times.
75. Steatogenes elegans (Steindachner).
Though this well-marked form was found to be rather common in the market at Para it has not been reported except at the mouth of the Rio Negro and in the Rio Jurua. It agrees very well with the description and picture of the type, though it differs from the latter in having the tail a little more slender and tapering to a finer point, and in the anal not stopping so abruptly posteriorly but gradually growing lower until it disappears. It has the same number of anal rays.
76. Higenmannia virescens (Valenciennes).
This species was found to be common in the market at Para. Most of the specimens have the ventral outline more strongly arched than the dorsal, as alleged for Ezgenmannia humboldti, and specimens of LE. virescens mentioned by Dr. Eigenmann from Rio Grande do Sul. Others have both outlines equally arched. ‘The character is very evidently due to preservation and cannot be used in classification. In the thick head and other characters these specimens agree very well with current descriptions. 77. Sternopygus macrurus Bloch and Schneider.
Several specimens of this form were taken at Para.
The life color is dark olive-green on the back, shading downward to bluish-slate color on the lower parts. There is a dark bluish spot above >