It. Lydekker — Mordwell and other CrocodiUans. 309 



four above-mentioned names previously applied by Meyer) ; while 

 to another form, in which the nasals reach the nares, he gave the 

 name of Crocodilus Ebertsi. Both forms show the enlarged third 

 lower tooth characteristic of Diplocynodon, and from the equivalence 

 of the Mayence and Allier deposits and the specific identity of many 

 of their Mammals, the prima facie presumption is that they are 

 respectively identical with the two Allier forms. 



Turning once more to the Hordwell Crocodilian, an examination of 

 the skull figured by Owen in pi. vi. of his " Crocodilia, etc., of the 

 London Clay " (Mon. Pal. Soc), now in the British Museum (No. 

 30393), shows that it has the enlargement of the third lower tooth 

 characteristic of Diplocynodon ; and also that the smaller upper teeth 

 bite on the outer side of the lower ones as in the Alligators, instead 

 of interlocking with them as in the Crocodiles ; and I therefore 

 come to the conclusion that Pomel's reference of this species to 

 Diplocynodon is correct, and consequently that it should be known as 

 D. Hantoniensis. I should observe, moreover, that I think there is no 

 doubt but that Diplocynodon is a valid genus, presenting the peculiar 

 feature of the enlargement of the third lower tooth, but otherwise 

 intermediate between Alligator and that group of Crocodilus com- 

 prising the existing Indian C. palustris and the fossil G. Sivalensis. 

 As I shall allude more fully on a subsequent occasion to the dis- 

 tinctive features of the genus, I will only observe here that if it be 

 not adopted it would be necessary to include both it and Alligator in 

 Crocodilus. 



"With regard to the so-called Alligator Darwini, I cannot observe 

 from the characters of the figured imperfect skulls any characters by 

 which it can be distinguished from D. Hantoniensis ; but since it 

 occurs on a higher horizon it may be entitled to specific distinction, 

 and I therefore propose that it should be provisionally known as D. 

 Darwini ; the specific name being adopted in preference to either of 

 the four proposed by Von Meyer, which were never properly described 

 or figured. With this form D. Bateli, Pomel, is probably also identical, 

 but the unsatisfactory character afforded by the type renders it in- 

 advisable to adopt this name. With regard to the so-called Crocodilus 

 Ebertsi the figured cranium appears to me to show no characters by 

 which it can be specifically distinguished from the younger type 

 cranium of D. gracilis from Allier ; the difference in the contour of 

 the two being apparently merely due to the different ages of the two 

 specimens. 



It will be apparent from the above that all the so-called fossil 

 Alligators of the Old World really belong to the genus Diplocynodon; 

 and since the Crocodiles (0. palustris and C. Sivalensis) which 

 approach nearest to this genus in the structure of the cranium and 

 form of the maxillo-premaxillary suture on the palate are confined to 

 India,^ it becomes an interesting question to know whether the exist- 

 ing Alligator recently described from China may not show signs of 

 affinity with Diplocynodon. 



' See Lydekker, " Palaeontologia Indica " (Mem. Geol. Surv. Ind.), ser. 10, vol. 

 iii. p. 216 (1886). 



