Arthur Smith Woodward — British Fossil Crocodilia. 509 



Dixoni, founding the species upon portions of the mandible and 

 teeth, and provisionally associating with these a slender femur and 

 vertebrce. 



But the most completely known of British Eocene forms is the 

 Crocodilus Hastingsice, Owen,^ of which the more or less perfect 

 remains occur abundantly in certain horizons in the Hordwell Cliffs, 

 Hampshire. With the exception of the characters of the limb-bones 

 and scutes, the osteology of this species was very fully made known 

 in Sir Eichard Owen's monograph ; ^ and the dermal armour has 

 been subsequently described by Prof. Huxley.^ As the result of 

 these studies, there appears to be almost decided proof that only a 

 single crocodilian form occurs in the Hordwell Beds, and that Searles 

 Wood's Alligator Hantoniensis * is thus merely a variety.® C. Hast- 

 ingsice, indeed, combines the characters both of Crocodiles and 

 Alligators to a remarkable extent; and it also possesses some features 

 that would quite entitle it to rank as a distinct genus, were it con- 

 sidered desirable to recognize as such certain early procoelian types 

 so distinguished in North America. 



None of the British Eocene species appear to have received further 

 elucidation by discoveries on the Continent, and the writer has only 

 succeeded in meeting with one case in which a foreign form is 

 identified with a species previously described in Britain. This is 

 Pictet's doubtful reference of some fragmentary fossils from the 

 Swiss Eocenes to Crocodilus ITn sting sice, Ovven.^ 



With the close of Eocene times, the history of the Crocodilia in 

 British areas seems to have ended ; and the latest species yet recorded 

 in Europe appears to be that mentioned by Gervais' as found in the 

 Pliocenes of Montpellier, France. 



Besides the descriptive Avorks already referred to, the English 

 literature of the subject also comprises some valuable general studies, 

 and in the foremost rank may be placed Prof. Huxley's now classical 

 memoir on the Evolution of the Crocodilia, read before the Geo- 

 logical Society in 1875.^ The well-known division of the order into 

 the three sub-orders of Pakasuchia, Mesosuchia, and Eusuchia, is 

 here first proposed, and appears to have met with almost universal 



1 E. Owen, " On the Fossils obtained by the Marchioness of Hastings from the 

 Freshwater Eocene Beds of the Hordle Cliffs," Brit. Assoc. Eep. 1847, Trans. 

 Sections, p. 65. 



^ R. Owen, op. cit. pp. 37-42, pis. vi.-ix. ; xii. figs. 2, 5. 



^ T. H. Huxley, paper already cited, in Quart. Journ. Geol. Soc. vol. xv. 



* Searles V. Wood, " On the Discovery of an Alligator and of several new 

 Mammalia in the Hordwell Cliff," Charlesworth's "London Geological Journal" 

 1846, p. 6, pis. 1, 6, 7. 



■^ It is interesting to notice that Prof. Cope has described a curious specimen of a 

 South American Alligator, in which the lower " canine " on one side fits into a notch, 

 ■while on the other the corresponding tooth is received in a pit (Trans. Amer. Phil. 

 Soc. vol. xiv. 1869, p 83). 



^ F. J. Pictet, " Paleontologie Suisse. — Vertebres de la Faune eocene," p. 89, 

 pi. vii. 



■' P. Gervais, " Zoologie et Paleontologie fran9aises," 2nd edit. (1859), p. 443, 

 pi. lix. fig. 2 ; pi. Ivii. fig. 7. 



8 Quart. Journ. Geol. Soc. vol. xxxi. pp. 423-438, pl. xix. 



