52 ICHTHYOPTERYGIA. 



** Ichthyosaurus breviceps, Owen \ 



Apparently closely allied to /. communis, but with the cranial 

 rostrum unusually short, and not exceeding in length twice the 

 longer diameter of the orbit. In the type specimen there are but 

 three bones in the third transverse row of the pelvic paddle, which 

 if constant may serve to confirm the right of this form to specific 

 distinction from /. communis. The large cranium referred by Owen 

 to the present species is entered under the head of /. platyodon. 



Hob. Europe (England). 



43006. Slab showing the left lateral aspect of a small skeleton ; 



(Fig.) from the Lower Lias of Lyme-Eegis, Dorsetshire. The 

 type specimen. Figured by Owen in his ' Liassic Reptilia,' 

 pt. iii. pi. xxix. fig. 2. The skull and limbs are well 

 preserved. The length of the cranial rostrum is nearly 

 twice the longer diameter of the orbit. The pectoral 

 paddle has seven longitudinal rows of phalangeals and 

 closely resembles that of /. communis, No. 2001* (p. 44), 

 but only four rows are shown in the pelvic limb. It is 

 difficult to see how this specimen can be specifically 

 distinguished from the above mentioned skeleton of 

 I. communis, unless the difference in the number of bones 

 in the pelvic paddle be a constant character. Purchased. 



R. 216. Slab showing the left lateral aspect of a skeleton of smaller 

 size than the preceding ; from Lyme-Regis. The paddles 

 of the left side are shown, but the pelvic one is too imper- 

 fect for the determination of the arrangement of the bones. 

 The pectoral limb has six longitudinal rows ; and the tall 

 neural spines of the vertebrae are well shown. The rostrum 

 has a length equal to double the diameter of the orbit. 



Presented by F. Seymour Haden, Esq., 1882. 



39263. Slab exhibiting the right lateral aspect of a crushed cranium 

 agreeing in characters with those of the preceding speci- 

 mens ; from Lyme-Regis. The length of the rostrum is 

 somewhat less than twice the diameter of the orbit. 



No history. 



R. 1062. Slab exhibiting the right lateral aspect of a crushed 

 cranium, the anterior part of the vertebral column, and 

 right pectoral girdle and limb in a broken condition : not 

 improbably belonging to this form ; from Lyme-Regis. 



No history. 

 3 Liassic Reptilia (Mon. Tal. Soc). pt. iii. p. 109 (1881). 



