.Half-grown¢. Carapace 25 in.
.Skullofd. . Adult 2 (still living). Carapace 27 in.
.Adult2,stuffed. Type of the species. .Skullofg. i.Young(stillliving). Carapace. .
Young, stuffed. Carapace 7 in.
. Adult ¢. Carapace 38 in.
.Skullofa. .Adult¢,stuffed. Carapace 34 in.
.Skullofc. .Adult¢,stuffed. Carapace38in. .Skullofe. g.Cervicalvertebreofe. LIST OF SPECIMENS. Tagus Cove, North Albemarle. 2) +) Tagus Cove, North Albemarle. Commander Cookson’s Collection. 76.6.21.42. Ditto. 76. 6. 21. 42. Ditto.
Purchased. 75. 12. 29. L. 75.12.29.1. Commander Cookson’s Collection. 13.
TESTUDO EPHIPPIUM. 74,6.1.6. 14.
Trestupo ABINGDONII. A bingdon Island, 3) Commander Cookson’s Collection. 76.6.21.40. Ditto. 76. 6. 21. 39. Ditto. 76. 6. 21. 39. Ditto. 76. 6. 21. 38. Ditto. 76. 6. 21. 38. Ditto. 76. 6. 21. 44.
18 THE RACES OF THE ALDABRA GROUP.
ALL the living gigantic Tortoises which have been brought to Europe from the Indian Ocean within the last forty years are distinguished by the presence of a nuchal shield, convex cranium, and narrow obturatoric bridge. Whenever it has been possible to trace their origin this was found to be Aldabra, a group of small islands north-west of Madagascar, situated in lat. 9° 25’ S., long. 46° 20’ KE. Although the majority of the specimens were shipped at Mauritius or the Seychelles, they had been brought there, in the first instance, from Aldabra, to be kept as curiosities or for the sake of their flesh or that of their progeny, which, in that suitable climate, they annually yielded to their owners with great regularity.
It is not at all impossible, nay, probable, that some of the other insignificant islands which are scattered in the same part of the Indian Ocean likewise harboured this Chelonian type; but of this I cannot find anywhere in the old records positive evidence. If it was so, the Tortoises were speedily exterminated, as the islands, from their small size, could not offer to them any place of effectual concealment. ‘These islands seem to have been formerly much more frequently visited by ships on their way to or from India than at present, when they are rather avoided.
Among the specimens united by the common characters stated above, not unimportant differences may be observed; they are difficult to reconcile with our ideas about the amount of variability within the limits of the same species or race; but we can account for them by assuming that the animals came from different though neighbouring islands. More especially the islands of which the Aldabra group consists are separated by narrow deep channels of the sea, perfectly impassable to animals so helpless in the water as Land-Tortoises. In other respects the islands are described as covered with verdure, low tangled bushes interspersed with patches of white sand. Two of the islands are rather low, hummocky near the centre. ‘The third island is the largest, extending about eighteen sea-miles in length and two or four miles in breadth ; it is much higher than the others, and partly covered with very high trees, that may be seen eight or nine leagues from the deck of a moderate-sized ship. Besides these three larger islands, there are several very small outlying islets. The first record of the existence of Land-Tortoises in Aldabra I find on a map of this group given by
THE RACES OF ALDABRA. 19 Dalrymple from the observations made in the boat ‘Charles’ and tartan ‘ Elizabeth ’ in 1744, where, the author adds, “ they found a great many Land-turtle much larger than those at Rodrigue.” Our knowledge of the configuration of these islands is still so incomplete that it will be useful to reproduce Dalrymple’s chart ; it is clearly faulty in its north-eastern portion (where the channel between the second and third main islands is omitted), but gives some idea of the smaller islets in the lagoon. AtpazBra (from Dalrymple). On applying to the Hydrographer, Capt. Evans, C.B., for more recent information, he, with his usual kindness, directed my attention to an unpublished chart deposited by the late Admiral W. F. W. Owen in the archives of the Admiralty, and reproduced here (p. 20) with the permission of the hydrographer. It appears that the group was partially surveyed by Lieut. R. Owen, of H.M.S. ‘ Leven,’ in 1824, which, with H.M.S. ‘ Barracouta, was engaged at that time, under the command of Capt. W. F. W. Owen, in the exploration of this part of the Indian Ocean*. This is at present the most reliable *See‘NarrativeofVoyagestoExploretheShoresofAfrica,Arabia,andMadagascar,performedinH.M. ships“‘Leven”and“Barracouta,”underthedirectionofCapt.W.F.W.Owen,R.N.’2vols.8vo,Lond. 1833.Nocompleteandcontinuousdetailedaccountoftheworkofthoseshipsisgiveninthat‘Narrative;’ and more especially I am unable to find Lieut.
Owen’s visit to Aldabra mentioned. D2
20 THE RACES OF ALDABRA. chart of the group; and the parts of the coast-line actually seen and surveyed by Lieut. Owen are distinctly shown. As he gives the depth of the lagoon, he must have entered a ee CTIA AW.
LILLLLL CART , a ain RM SNH) nl demo q Milly. un vl.
Abundanee of land tortoise d fathom SI a OE eS ee a ante N Moy UA SUI Sp ye WS DAY enya ea 5 SeaMiles Hodoul P?
Lat 9°26/30/S, Long 46:3430°E approx umd Fe ALDABRA, (SurveyedbyLieut.Rich.Owen,R.N.,H.M.S.‘Leven,’1824.) ee it in boats, although he does not take further notice of the smaller islands, the surveying of which could not possibly be of any importance to the navigator. Aldabra has never been permanently inhabited—a circumstance by which the Tortoises were saved from utter extinction. Although the number was constantly being thinned by the raids of crews of passing whalers or fishing-vessels, a small remnant found a safe refuge in the tangled and almost impenetrable thickets; if these be allowed to be invaded or cut down, the Aldabra Tortoise will disappear, like those of the Mascarenes *.
* A report having reached England that a permanent settlement was about to be made on Aldabra, steps weretakentosecuretheprotectionoftheTortoises;andthiswillnotbeaninappropriateplacetoputon record a memorial sent to the Government of Mauritius, as well as the replies thereto :— “To His Excellency the Hon. Sir Arthur Hamilton Gordon, K.C.M.G., Governor and Commander-in-Chief of Mauritius and its dependencies. “We, the undersigned, respectfully beg to call the attention of the Colonial Government of Mauritius to the imminent extermination of the Gigantic Land-Tortoises of the Mascarenes, commonly called ‘ Indian Tortoises.’ “2.
These animals were formerly abundant in the Mauritius, Réunion, Rodriguez, and perhaps other islands of the western part of the Indian Ocean. Being highly esteemed as food, easy of capture and transport, they formed for many years a staple supply to ships touching at those islands for refreshment.
TESTUDO ELEPHANTINA. 21 1.
TESTUDO ELEPHANTINA. After having carefully studied the detailed description given by Duméril and Bibron under the above heading, it seems to me very probable that several specifically distinct forms were included in it. The scutes are described by the French herpetologists as sometimes striated, sometimes entirely smooth, whilst I exclude from this species all individuals with perfectly smooth scutes, the absence of sculpture not being dependent either on sex or entirely on age. On the other hand I refer to this species specimens of black as well as brown coloration, whilst the latter is stated to be one of the characteristics of 7. elephantina in the ‘ Erpétologie générale. Thus the limits assigned to this species by its authors do not appear to coincide with those determined by myself. ‘<3.Nomeansbeingtakenfortheirprotection,theyhavebecomeextinctinnearlyalltheseislands;and Aldabraisnowtheonlylocalitywherethelastremainsofthisanimalformareknowntoexistinastateof nature. «4,WehavebeeninformedthattheGovernmentofMauritiushavegrantedaconcessionofAldabrato partieswhointendtocutthetimberonthisisland.Ifthisprojectbecarriedout,orifotherwisetheisland isoccupied,itistobefeared,nay,certain,thatallthetortoisesremaininginthislimitedareawillbe destroyed by the workmen employed. “5,WewouldthereforeearnestlysubmitittotheconsiderationofyourExcellencywhetheritwouldnot be practicable that the Government of Mauritius should cause as many of these animals as possible to be collected before the wood-cutting parties or others land, with the view of their being transferred to the Mauritius or the Seychelle Islands, where they might be deposited in some enclosed ground or park belonging to the Government, and protected as property of the Colony. «6.
In support of the statement above made and the plan now submitted to the Mauritius Government, the following passages may be quoted from Grant’s ‘ History of Mauritius,’ 1801, 4to :— «<«We(inMauritius)possessagreatabundanceofbothland-andsea-turtle,whicharenotonlyagreat resourceforthesupplyofourordinarywants,butservetobarterwiththecrewsofships’(p.194). «<ThebestproductionofRodriguezistheland-turtle,whichisingreatabundance.Smallvesselsare constantly employed in transporting them by thousands to the Isle of Mauritius for the service of the hospital’ (p.
100). «««Theprincipalpointofview(inRodriguez)is,first,theFrenchGovernor’shouse,orratherthatofthe Superintendent appointed by the Governor of the Isle of France to direct the cultivation of the gardens there and to overlook the park of land-turtles; secondly, the park of land-turtles, which is on the sea-shore facing the house’ (p.
101). “7, The rescue and protection of these animals is, however, recommended to the Colonial Government less on account of their utility (which now-a-days might be questioned in consideration of their diminished number, reduced size, and slow growth, and of the greatly improved system of provisioning ships, which renders the crews independent of such casual assistance) than on account of the great scientific interest attached to them. WiththeexceptionofasimilartortoiseintheGalapagosIslands(nowalsofastdisappearing),thatofthe Mascarenes is the only surviving link reminding us of those still more gigantic forms which once inhabited thecontinentofIndiainapastgeologicalage.Itisoneofthefewremnantsofacuriousgroupofanimals onceexistingonalargesubmergedcontinent,ofwhichtheMascarenesformedthehighestpoints.It flourishedwiththeDodoandSolitaire;andwhilstitisamatteroflastingregretthatnotevenafew individuals of these curious birds should have had a chance of surviving the lawless and disturbed condition of
22, THE RACES OF ALDABRA. The amount of variation in the form of the carapace is considerable, much greater than in any of the other Gigantic Land-Tortoises; and the differences between these variations are quite equal, and in some measure analogous, to those observed between some of the Galapagos Tortoises for which I have adopted distinct specific denominations. But, whilst in the latter such external modifications are combined with marked features of the skull and other parts of the skeleton, the skulls of the varieties of T. elephantina surprisingly agree in the details of form with one another. It is this species to which J. E. Gray and others applied the name of Testudo indica par excellence; finding that the varieties of external form closely resemble, and almost repeat, those from the Galapagos, they included in it, more or less, all the other Gigantic Land-Tortoises. ‘That name must be restricted to the species described by Perrault (Mém. pour servir 4 Vhist. nat. des anim. 1676, p. 193, c. tab.). Characteristic of this species is the concentric striation of the scutes, which, most distinct in young specimens, never disappears entirely, not even in the largest and oldest examples; then the declivity of the first vertebral scute; the moderate reversion of the margins of the carapace; the undivided caudal scute*; the broad skull, with the posterior margin of the paroccipital not excised. The specimens available for examination may be grouped as follows :— past centuries, it is confidently hoped that the present Government and people, who support the ‘ Natural-HistorySocietyofMauritius,’willfindameansofsavingthelastexamplesofacontemporaryoftheDodoand Solitaire. (Signed) “ Josepa D. Hooxrr. “H.B.E.Frere. * Ricn. OWEN. “ CHarirs Darwin. “ Atrrep Newron. “JounKirk. “ ALBERT GUNTHER.” “London, April 1874.” This memorial received the full attention of Sir A.
Gordon, who, in his reply, promised that the lessee should beboundtoprotecttheanimals,andtoremitannuallytoMauritiusapairoflivingones,which,withothers acquired by purchase, would be preserved in a paddock of the Botanic Gardens at Pamplemousses. On Sir A.
Gordon leaving Mauritius soon afterwards, M.
Bouton, the Secretary of the Royal Society of Mauritius, submittedthemattertohissuccessor,SirA.P.Phayre,whorepliedasfollows:— “My prar M.
Bovroy,—I return you the papers received from you regarding the gigantic Land-Tortoises. I have made arrangements with the Chief Civil Commissioner in order to have those on Aldabra preserved. “ Believe me, ‘«‘ Yours sincerely, (Signed) CTA. ye HAR Ee * But for this character I should regard Testudo gigantea of Schweigger and Dum¢ril and Bibron as identical with7’.elephantina.Possiblythedivisionofthisscuteisonlyanindividualpeculiarityofthespecimenon which this species was founded.
TESTUDO ELEPHANTINA. 23 A. Each vertebral scute is raised into a high protuberance, more or less confined to the areolar region.
e. Carapace broad, black or of a dark brown colour. 6. Carapace narrower, horn-coloured. B. Vertebral scutes not raised in the middle, flat. y. Carapace broad, black.
Of these three varieties « may be compared to 7. nigrita, B to T. vicina, and y to T. elephantopus from the Galapagos Islands. The materials which I refer to 7. elephantina are the following :— Var.a.
a. An adult stuffed male, carapace 39 inches long, in the British Museum. Black. 6. Skull of the same individual.
c. Anadult male, carapace 49 inches long, from Aldabra, in the British Museum. Brown. This specimen is one of the pair imported in 1875 from the Seychelles (see ‘ Nature,’ 1875, p. 260).
Skeleton of the same individual.
An adult stuffed female, carapace 273 inches long, in the British Museum. Black. Skull of the same individual.
Carapace of a young specimen, 14 inches long, in the British Museum. Var.£.
. Carapace of adult male, 40 inches long, in the British Museum. ac = ~~ Var.y.
2. Carapace of an adult male, without scutes, 40 inches long, transferred from the Old Collection in Montague House (with cast of head and feet). . An adult stuffed male, carapace 43 inches long, in the Free Public Museum, Liverpool. The Curator, Mr. T. J. Moore, has kindly informed me that this specimen was brought alive from the Cape of Good Hope by a collector sent about the year 1840 by the then Earl of Derby to South Africa to collect living antelopes &c. It lived for a few months only at Knowsley. k. Skull, bones of the forearm and lower leg, with the majority of the carpals and o tarsals of the same individual.
NN . Skeleton of a half-grown male (sternum missing), carapace 31 inches long, in the BritishMuseum.
m. Carapace (with sternum) of a half-grown male, 294 inches long, in the British Museum.
Finally— n. A skull, humerus, femur, and scapula of one or more large examples in the British
24 THE RACES OF ALDABRA. Museum cannot be referred to either of these three varieties, nothing being known of the carapaces or any other part of the animals to which they belonged. o. Skull of a half-grown example in the British Museum, figured in Gray’s ‘ Catal. of Shield-Reptiles’ (4to), pl. 35. fig. 1. Variety«. In the adult male specimen the carapace (Plate III.) is very high, very convex in every direction, and nearly equally broad in front and behind. The anterior vertebral scute slopes rapidly from a protuberance near its hind margin down to the nuchal plate. The anterior and posterior free margins of the carapace are somewhat turned outwards, but not reverted, with shallow notches between the marginal scutes. The caudal plate is neither bent inwards nor outwards, its surface being a plane. The middle of each of the four posterior vertebrals is raised into a high hump, which gradually slopes down towards the margins. Also the costals participate in some measure in this peculiarity; but their most prominent part has an eccentric position, and is limited to the upper half of each scute. In all the scutes the smooth areolar portion can be clearly distinguished from the very broad striated portion, although the striz are rather broad and somewhat obsolete in the vertebrals, but well-developed in the marginals. Nuchal plate of moderate size, rather longer than broad. ‘The sternum (Plate IV. fig. A) is deeply concave, broad, with the anterior portion somewhat contracted, truncated in front and behind. The shell is very thick and heavy *, the substance of the caudal plates and of the lateral portion of the abdominals being particularly thickened and callous. In the large specimen, ¢, a section of this portion shows a thickness of three inches— the osseous substance, however, not being solid, but cavernous. The upper surface of the head (Plates I. & II.) is covered with large irregular shields, of which two, covering the frontal region, are by far the largest, about thrice as long as broad. The neck is shorter than in any of the Galapagos Tortoises. The scutes on the anterior side of the fore leg are separated from the smaller ones covering the hinder side by a longitudinal series of large scutes, which run along the outer edge of the forearm. ‘The tail is about 10 inches long, and provided with a large, flat, terminal claw. * Fatconer, in his notes on Colossochelys atlas (Paleontolog. Mem.
vol.
i.
p.
378), states that “ the thickness ofboneintheconvexityisalmostinaninverseratiotothesize.Thephysiologicalreasonofthisis,thatthe smallertheanimal,themoreliableitistoinjury,anditrequiresagreaterarchtosustainit.”Thisviewis notconfirmedbyanexaminationofthelivingTortoises;theAldabraspeciesisaslargeasthosefromthe Galapagos,andevenlargerthanoneoftheselatter,yetithasamuchthickershell.Weshallseethatthe extinct Mascarene species agree with the Galapagos Tortoises in this respect. Perhaps the cause of this is to be sought in the small quantity of earthy matter contained in the food on which those animals chiefly subsist. A living Galapagos Tortoise in my possession preferred the petals of a Westeria to every other plant. Of course, by the thinness of the shell its weight is much reduced ; and these Tortoises are therefore able to walk faster and tocarrytheshellhigherabovethegroundthanthethick-shelledspecies.Thethinnessoftheshellandthe slender osseous framework of the limbs are, in fact, characters correlated to each other.