Vol. 70.] VERTEBRATES FROM BRITISH EAST AFRICA. 185 



individual from Bed 31 at Kachuku ; in this the sculpture is quite 

 similar to that of the type carapace. 



The collection also includes some fragments of the shell of a 

 species of Trionyx with fine vermiculate sculpture, but the remains 

 are insufficient for determination. There is, too, a fragment of the 

 middle of a large carapace bearing a sculpture of numerous shallow 

 pits ; this may indicate the presence of a form allied to CJiitra 

 indica. 



Order CROCODILIA. 



The Crocodiles are represented by teeth, scutes, and a few frag- 

 ments of bones. One type of tooth is thick and blunt-crowned, 

 almost circular in section, but with distinct anterior and posterior 

 carinse ; the enamel is raised into fine wrinkles. These teeth pro- 

 bably belong to a Crocodile much like the recent Cr. niloticus. 

 There are also some slender conical teeth with very sharp points, 

 and a somewhat curved crown covered with enamel, raised at 

 Tegular intervals into well-marked ridges running from base to 

 tip ; in some cases, there are slightly developed anterior and 

 posterior carinse. This type of tooth probably belonged to a long- 

 snouted ga vial-like form, not otherwise represented in the collection, 

 except perhaps by some fragments of maxilla. 



Finally, among a number of small teeth collected in Bed 24 

 there is one with a somewhat compressed lanceolate crown, the 

 •edges of which, except at the worn tip, bear a fine serration at 

 right angles to the border (PI. XXVIII, fig. 8). This tooth is 

 extraordinarily like those of some Carnivorous Dinosaurs (for 

 instance, Thecodontosaiiras); as it shows no signs, however, of 

 derivation from older beds, it can hardlv belong; to a member of 

 that group, but is most probably Crocodilian. Somewhat similar 

 serrated teeth have been described by Cuvier l as belonging to 

 a Crocodile, remains of which are common in Eocene beds near 

 Argenton. J. E. Gra}'' 2 subsequently called this species Crocodilus 

 roJlinatii, but afterwards it was referred to a separate genus 

 Prist ichampsa by P. Gervais. 3 In this the teeth are similarly 

 compressed and serrated, and it seems likely that the specimen 

 here described indicates the survival in Africa of a similar type 

 of Crocodile until the Miocene Period. Possibly some of the 

 strongly sculptured scutes, the smaller vertebra?, and other bones 

 may belong to the same animal. 



1 'Recherches sur les Ossemens fossiles ' 2nded. vol. v, pt. 2 (1824) p. 166 

 & pi. x, figs. 14-17, 21, 22. 



- 'Synopsis Reptilmm ' 1831, p. 61. 



3 ' Zoologie & Paleontologie Fran9aises' 2nd ed. (1859) p. 446 & pi. lvii, 

 figs. 19-21, pi. lix, figs. 3-5. 



o2 



