ICHTHYOSATJRIDiE. 



80 



Ichthyosaurus latifrons, Konig \ 

 Svn. Ichthyosaurus longirostris, Owen 2 . 

 Ichthyosaurus laticeps, Owen 3 . 

 (?) Ichthyosaurus longirostris, Jager 4 . 



The cranial rostrum still more elongated and slender than in 1. 

 tenuirostris, its length in some cases exceeding six times the diameter 



Fig. 31. 



Ichthyosaurus latifrons. — Left lateral aspect of the skull ; from the Lower Lias 

 of Barrow-on-Soar. About £. (After Owen.) 



of the orbit ; orbit relatively very large ; fronto-nasal region very 



wide and somewhat convex, narrowing sud- 

 denly towards the rostrum, and facial profile 



forming a sudden dip in advance of orbit; 



parietals forming an acute ridge between 



supratemporal fossae. Parietal foramen placed 



entirely in frontals. Teeth minute, and ap- 

 parently in some instances disappearing from 



the anterior part of the rostrum in the adult. 



Paddles (fig. 32) very similar to those of /. 



tenuirostris ; but the humerus relatively more 



slender and less expanded distally. Scapula 



more like that of /. platyodon. 



There appear no characters by which /. 



longirostris, Owen, can be distinguished from 



this species, which occurs in both the Upper 



and Lower Lias. The type specimens of 



I. longirostris, Jager, from the Upper Lias 



of Wurtemberg, agree with this species in the Ichthyosaurus latifrons. 



— Dorsal aspect of the 

 left 5 pectoral limb ; 

 from the Lower Lias of 

 Barrow-on-Soar. h, 

 humerus; r, radius ; 

 u, ulna ; J, intermedi- 

 um, j [After Owen.) 



extreme length of the rostrum, and are there 

 fore probably specifically the same. The 

 apparent identity of /. longirostris with this 

 species is mentioned by Tate and Blake in 

 their 'Yorkshire Lias,' p. 254 (1870). 



JIab. Europe (England and Wurtemberg). 



1 Icones Foss. Sectiles, pi. xix. (1825). 



2 Liassic Rept ilia (Mon. Pal. Boc), pt. iii. p. 124 (1881). Also mentioned by 

 Mantell in his 'Petrifactions and their Teachings,' p. 385 (1851). 



3 Op. cit. p. 120. — Errorim. 



1 Nova Acta Ac. Ctes. Leop.-Car. vol. xxv. pt. 2, p. 939 ct scq. (1866). 

 5 This figure is really a reversed view of the right limb, but it is less liable to 

 cause confusion by terming it left. 



