NATURE 



\Aug. 12, 1875 



The following day found Prof. Wdhler unbent by the 

 honorary burden of the 31st of July, and some privileged 

 friends and pupils had the pleasure of seeing him working 

 at the analysis of a new mineral with the same zeal he 

 would have shown fifty years ago. This formed the 

 most pleasant part of the Wohler Festival, being a 

 hopeful sign of the vigour and power left to this great 

 man. The readers of Nature (vol. xii. p. 179) were 

 able, only a few weeks ago, by the perusal of extracts from 

 charming recollections of Prof. Wohler's youth, to witness 

 a similar proof. In fact, his youth has accompanied him 

 into his old age, A. Oppenheim 



THE GIGANTIC LAND TORTOISES OF THE 



MASCARENE AND GALAPAGOS ISLANDS* 



III. 



I WILL now indicate the characteristics of the different 

 races which I have been able to recognise in the 

 materials to which I have had access. 



It has been mentioned above that the principal mark 

 of distinction is in the form of the skull : some species 

 having a depressed skull with the surface flat above, 

 whilst in others it is much higher and convex above. 

 Hand-in-hand with this difference in the skull goes 

 another in the pelvis ; the flat-headed Tortoises having a 

 broad, horizontally dilated bridge between the obturator 

 foramina, whilst in the round-headed form the bridge is 

 vertically compressed. Such a distinction might have 

 been expected between the Galapagos Tortoises on the 

 one hand, and the Mascarene races on the other ; but 

 what justly excites our surprise is that the Galapagos 

 Tortoises and the extinct forms of the Mascarenes 

 belong to the same (the flat^headed) type and that, there- 

 fore, a much greater affinity exists between them, than 

 between the extinct and living races of the Mascarenes. 



I.— Flat-headed Type 

 A. The Galapagos Tortoises may be recognised by the 

 invariable absence of a nuchal plate, by the convergence 

 of the posterior margins of the two gular plates which 

 never form a straight line, by the black colour of the 

 shell, by a large scute of the inner side of the elbow, by 

 the double alveolar ridge of their jaws. Among the 

 carapaces which I have examined I can distinguish five 

 forms ; of the first four severally two are more nearly 

 related to each other than to the other pair, the fifth 

 being intermediate between these two pairs. The degree 

 of distinctness and affinity which obtains in the carapaces 

 is expressed clearly and in exactly the same manner in 

 the skulls, as will be seen from the following character- 

 istics : — 



1. In the first species {Testudo elephantopus of Harlan) 

 the shell is broad and depressed, with the upper anterior 

 profile sub-horizontal in the male, and with corrugated 

 but not deeply sculptured plates. Sternum truncated 

 behtnd. The snout is very short. Skull with an im- 

 mensely developed and raised occipital crest, with a 

 sharp outer pterygoid edge, and a deep recess in front of 

 the occipital condyle. The skeleton of a fully adult male 

 example and one of an immature female are in the Oxford 

 Museum and the collection of the Royal College of Sur- 

 geons. Young individuals are by no means scarce in 

 collections. Either this species or the next appears to 

 have inhabited James' Island. 



2. Testudo nigrita has likewise a broad shell which, 

 however, is considerably higher than in the former 

 species ; the anterior profile in the male is declivous, and 

 the plates are deeply sculptured. Sternum with a tri- 



* The substance of this article is contained in a paper read by the author 

 before the Royal Society in June, 1847, and will appear in the forthcoming 

 volume of the "Philosophical Transactions," and to which I must refer for 

 the scientific portion and other details. Some facts which have come to my 

 knowledge subs«qu«otly to the reading of this paper, are added. Continued 

 from p. 261. 



angular excision behind. The snout is longer and the 

 occipital crest low ; but the ©uter pterygoid edge is 

 equally sharp, and the recess in front of the occipital 

 condyle equally deep as in T. elephantopus. The principal 

 specimens examined by myself of this species, are one 41 

 inches long, in the British Museum ; the type of the spe- 

 cies (described and named by Dumeril and Borbron) in 

 the collection of the Royal College of Surgeons ; and the 

 large skull in the British Museum, figured by Dr, Gray 

 under the name of Testudo planiceps. 



3. Porter's account of the race inhabiting Charles 

 Island is sufficiently characteristic to enable us to recog- 

 nise it in an adult specimen, the shell of which is elongate, 

 compressed into the form of a Spanish saddle, and of a 

 dull colour without any polish. The sterum is truncated 

 behind. Skull with the outer pterygoid edge flattened, 

 with the tympanic cavity much produced backwards, and 

 without recess in front of the occipital condyle. The only 

 adult example wdich I have examined is 33 inches long, 

 and belongs to the Museum of Science and Arts, Edin- 

 burgh. It was lent to me by the Director, Mr. T. C. 

 Archer, who most kindly allowed the skull and limb- 

 bones to be extracted, which could be effected without the 

 least injury to the outward appearance of the specimen. 

 This species I have named Testudo epMppium. 



4. The smallest of the Galapagos Tortoises is one for 

 which I have proposed the name Testudo microphyes, the 

 carapace of a fully adult male being only 22^ inches long. 

 We may presume that this specimen, for an examination 

 of which I am indebted to the Museum Committee of the 

 Royal Institution of Liverpool, is a representative of the 

 race from Hood's Island, Porter having expressly stated 

 that the tortoises of that island are small, and similar to 

 those of Charles Island, Indeed, the shell is elongate as 

 in T. ephippium, but the anterior profile is declivous. 

 The skull has the characteristics of a young skull of one 

 of its more gigantic congeners ; the outer pterygoid edge 

 is flat, and there is no recess in front of the occipital 

 condyle, as in the species from Charles Island, 



5. In the last species {Testtcdo vLina) the skull is 

 depressed as in the first, with the upper exterior profile 

 sub-horizontal in the male, and with the lateral anterior 

 margins reverted so as to approach the peculiar shape of 

 T. ephippiuiii. The concentric sculpture of the plates is 

 distinct. Sternum of quite a peculiar shape, much con- 

 stricted and produced in front, and expanded and excised 

 behind. The skull is extremely similar to that of T. 

 ep)hippiu7n. Unfortunately nothing is known of the 

 history of the adult male example which formerly was in 

 the possession of Prof. Huxley and ceded by him to the 

 collection of the British Museum, 



B, The Mauritian Tortoises. — It would be a matter 

 of considerable interest to ascertain whether the tor- 

 toises of Mauritius lacked the nuchal plate, like the 

 Galapagos races to which in other respects they are 

 so closely related. The only carapace which I have 

 seen is deprived of the epidermoid scutes, and, besides, 

 so much injured in the nuchal region that it is im- 

 possible to determine the absence or presence of a 

 nuchal plate. But the Mauritian tortoises were charac- 

 terised by a peculiarity hitherto unknown among recent 

 land tortoises, viz., by a treble serrated dental ridge along 

 the lower jaw. 



The examination of a considerable number of bones, 

 part of which were obtained during the search for Dodo- 

 bones, and are now in the British Museum, whilst for 

 others from the district of Flacq I am indebted to M, 

 Bouton, has convinced me of a multiplicity of species in 

 this island. The majority of the bones were found near 

 Mahe'bourg, in a ravine of no great depth or steepness, 

 which apparently once conveyed to the sea the drainings 

 of a considerable extent of circumjacent land, but which 

 has been stopped to seaward most likely for ages by an 

 accumulation of land. The outlet from this ravine having 



