SUPPLEMENT. 235 



The following specimens may indicate an immature 

 individual of this species. 



R. 1478. A series of associated bones ; from the Great Oolite of 

 Northampton. These comprise several imperfect cervical 

 and dorsal vertebrae, fragments of jaws, ribs, and other 

 bones, together with some teeth which may or may not be 

 associated. The cervical vertebrae, although smaller, agree 

 in form with those of No. R. 1477 ; and are quite 

 different from the smaller and more elongated type figured 

 by Phillips, he. cit. fig. 1, and referred to Teleosaurus 

 subulidens. Purchased, 1889. 



Order PARASUCHIA [supra, i. p. 123). 



According to Koken ] there is no middle Eustachian canal in this 

 group, the channel described as such being incorrectly named. 



Recent observations show that the skull of Phytosaurus is con- 

 structed so essentially on the Rhynchocephalian plan as to entail 

 the necessity of raising the Parasuchia to the rank of a distinct 

 order. The Crocodilia can, therefore, be much more exactly defined 

 than was previously possible. 



In the skull of Phytosaurus (Pt. I. pp. 124-5) the arrange- 

 ment of the temporal arcades is strictly the same as in Sphenodon ; 

 and a similar resemblance occurs in the structure of the palate — 

 notably in the junction of the vomer with the pterygoids, and the 

 relations of the palatines, pterygoids, and quadrates ; while in both 

 forms there is a vacuity on the occipital aspect between the quadrate 

 and quadrato-jugal. The great development of the premaxillary 

 rostrum of Phytosaurus is similar to the condition obtaining in the 

 Rhynchocephalian genus Ohampsosaurus and the Ichthyopterygia. 

 The abdominal ribs are of the chevron-like type found in Sphenodon, 

 and quite different from those of the Crocodilia. 



The Parasuchia, therefore, resemble the Rhynchocephalia and 

 Ichthyopterygia in the structure of the skull, abdominal ribs, and 

 probably of the clavicular arch ; w 7 hile they agree with the Croco- 

 dilia in the characters of the vertebra? and the dermal armour ; 

 their thecodont dentition being likewise an Archosaurian character. 

 It depends on the relative degree of importance attached to cranial 

 as opposed to vertebral and dermal characters whether the order 

 should be retained in the Archosaurian or transferred to the 

 Streptostylic Branch. The Aetosauria should probably be included 

 in the Parasuchia. 



• l Zeitschr. deutsch. geol. Ges. vol. xl. p. 761 (1889). 



