422 Dr. A. Giinther on Gigantic Land-Tortoises. [June 18, 



that the different islands of the group are inhabited by different races, is 

 perfectly correct ; and he distinguishes four species, the adults of which 

 are characterized as follows : 



A. Shell broad, with more or less corrugated plates. STcull with the' 

 palatal region concave ; outer pterygoid edge sharp in its entire length 

 or for the greater part of its length ; a deep recess in front of the occi- 

 pital condyle ; anterior wall of the entrance of the tympanic cavity con- 

 stricted. One of the two species is from James Island. 



1. Shell depressed, with the upper anterior profile subhorizontal in the 

 male, and with the striae of the plates not deeply sculptured ; sternum 

 truncated behind. Skull with the facial portion very short, and with an 

 immensely developed and raised occipital crest. Testudo elephantopus 

 (Harlan). 



2. Shell much higher, with the upper anterior profile declivous in the 

 male, and with the striae deeply sculptured ; sternum excised behind. 

 Skull with the facial portion much longer, and with low occipital crest. 

 Testudo nigrita (Dum. & Bibr.). 



B. Shell oblong, smooth. STcull with the palatal region shallow ; the 

 outer pterygoid edge expanded in its whole length ; no deep recess in 

 front of the occipital condyle ; anterior wall of the tympanic cavity not 

 constricted. 



3. Shell with some traces of former concentric striae, compressed ante- 

 riorly into the form of a " Spanish saddle " in the male ; sternum trun- 

 cated behind. STcull with the tympanic cavity much produced backwards. 

 Testudo ephippium (Grthr.), from Charles Island. Extinct. 



4. Shell perfectly smooth, with declivous anterior profile in the male, 

 and with truncated posterior extremity of the sternum. Skull resem- 

 bling that of the young of the larger species, with the tympanic case not 

 produced backwards. The smallest species. Testudo microphyes (Grthr.), 

 from Hood's Island. 



Part III. will contain the account of the still existing Tortoises of the 

 Mascarenes, and Part IV. that of the extinct species. 



Received June 9, 1874. 



PS. The author has just received from Professor Huxley the carapace 

 and skeleton of another adult male, which evidently belongs to a fifth species 

 of Galapagos Tortoises. With regard to the form of the carapace, it 

 resembles much that of T. elephantopus, the dorsal shell being depressed, 

 broad, with the upper profile nearly horizontal. Striae distinct, broad. 

 However, the skull differs widely from that of T. elephantopus, and has 

 all the characteristics of that of T. ephippium, from which it differs in 

 having a circular tympanic opening. The form of the sternum is quite 

 peculiar, the gular portion being much constricted and produced forwards, 

 whilst the opposite end is expanded into the large anal scutes and deeply 

 excised. This species may be named Testudo vicina. 



