Manchester Mcinoirs, Vol. h. {igw), No. l^. ii 



Their position favours this suggestion, and they can be 

 exactly paralleled in crushed skulls of Mystriosanrus. 



There is hence no reason for separating the skull 

 described as Petrosnchus laevidens from Macrorhynchus, 

 which Koken holds to be synonymous with Pholidosaiirus, 

 H. V Meyer, which has priority. 



All the skulls of PJiolidosaurns have a very elongated 

 rostrum, being of gavialoid proportions. The Petrosuchus 

 skull is damaged anteriorly, so that no direct evidence of 

 its length is possible. 



The lower jaw, which Owen theoretically associated 

 with the skull, is quite short, and seems to shew that the 



— o o o o ^rTr ^Q-Q-To— Q 



Fig. 4. I^ower jaw of Pholidosaurus ? decipietts, from tlie 

 ^liddle Purbeck of Swanage. x \. 



symphysis was short, only some 2 or 3cms. in length. 

 This jaw, in the posterior part not figured by Owen, has 

 an ornament of deep rounded pits like those on a 

 Goniopholis scute. The skull shews only a very faint 

 ornament of irregular shallow grooves, even the frontal 

 not bearing any deep pits. 



It is, in fact, certain that the skull and lower jaw 

 described as PetrosiicJms laevidens have nothing whatever 

 to do with one another. There is in the Manchester 

 Museum a portion of the right ramus of the lower jaw of 

 a crocodilian from the Middle Purbeck of Swanage 

 which agrees closely with that figured by Koken for 

 Pholidosaurus scliaumbersrensis. The ornament of this 



