AMERICAN AMPHICCELIAN CROCODILES 3 



matters are as satisfactory. It is evident that the type species of the 

 genus, B. harlani Meyer, is a broad-faced or brevirostrate form, but 

 I do not feel so sure that it has procoelous vertebrae. Harlan based 

 his species Crocodilus macrorhynchus Harlan (non- Blaine ville) upon 

 the larger part of the right mandible, which has been figured and 

 more fully described by Leidy.^ This mandible is very peculiar in 

 lacking, apparently, the large foramen, so characteristic of all 

 procoelian crocodiles, ancient and modern, and of the known amphi- 

 coehan forms, save certain species of Goniopholis" and other Goni- 

 opholididae, such as Pterosuchus.^ Indeed, the Parasuchia or Phy- 

 tosauria, which I would exclude from the Crocodiha in the widest 

 sense, have such a foramen. Cope later added another species, B. 

 tuberculatus,"^ to the genus, but I fail to find any positive evidence of 

 congenerousness with the type species, nor am I assured that the 

 form is brachystomous even. B. perrugosus Cope, which may be the 

 same as Crocodilus humilis Leidy, from the Laramie Cretaceous of 

 eastern Colorado, was only provisionally referred to the genus. ^ A 

 gigantic procoelian crocodile is not at all uncommon in the upper- 

 most Cretaceous of the West, as mentioned by Hatcher and as I 

 have seen from western Texas. No other evidence is forthcoming 

 that Bottosaurus has procoelous vertebras. If it really has, then an 

 important fact has been for the most part overlooked hitherto, the 

 presence of broad-faced crocodiles, with a short mandibular sym- 

 physis, from so low an horizon, forms which might stand in more 

 immediate ancestral relationship with the modern Crocodilidae than 

 do any of the known Tomistomidae (Rhynchosuchidae) of the Cre- 

 taceous. I cannot resist the suspicion that Bottosaurus will eventu- 

 ally be found to be an amphicoelian form. It is a remarkable fact, 

 as Koken has shown, ^ that the early longirostrate procceHan croco- 

 diles are scarcely distinguishable generically, save in their vertebrae, 

 from their contemporary longirostrate amphicoelian forms, and it is 



1 Leidy, Cretaceous Reptiles (1865), p. 2, Plate IV, Figs. 19-23. 



2 Owen, British Fossil Reptiles, Vol. I, p. 64;, Plate XLII, Fig. 2. 



3 Owen, Fossil Reptiles of the Wealden Formation (1878), Supplement VIII, p. 10. 



4 Cope, Exthict Batrachia, etc. (1865), p. 230. 



■i Cope, Cretaceous Veriebrata (1875), p. 68, Plate VI, Figs. 5-8. 

 ^Koken, Paleontologische Ahhandlungen (1887), Vol. Ill, p. 93. 



