1CHTHTOSAT7EIDJ3. OO 



38523. Slab showing the right lateral aspect of the anterior portion 

 {Fig.) of a smaller skeleton ; from the Lower Lias of Lyme- 

 Regis, Dorsetshire. The type specimen. The crashed 

 skull, the thoracic region (enclosing coprolitic matter), 

 and the ventral aspect of the left pectoral limb (fig. 22) 

 are shown. The right humerus and some scattered distal 

 bones of the paddle also remain ; and both coracoids are 

 shown. The anterior border of some of the first row of 

 phalangeals is notched, although not shown in the figure. 

 The skull bears a greater proportionate length to the 

 vertebral column than in the skeleton No. 41849 of 

 /. communis (p. 42) ; and in this respect this specimen 

 agrees with the preceding. The length of the skull is 

 0,292 (11-5 inches), and that of the pectoral limb 0,115 

 (4-5 inches). The length of the pectoral limb relatively 

 to that of the skull is therefore much greater than in 

 /. communis, No. 41849 ; the relative proportion of the 

 limb to the skull being about f. The phalangeals are 

 also relatively larger. The presence of six longitudinal 

 rows of phalangeals, and the entire anterior border of the 

 radius and the radiale forbid the reference of this specimen 

 to any member of the Longipinnate group ; and if it be 

 not specifically identical with the preceding specimen the 

 latter would seem to indicate another unnamed species. 



Purchased, 183G. 



Ichthyosaurus intermedins, Conybeare l . 



Syn. Ichthyosaurus chiroparamecostinus, Hawkins 2 . 



Distinguished from the type species by the following characters. 

 Teeth relatively smaller and longer, with the flutings on the crown 

 finer, and those on the root less strongly marked. Neural spines of 

 cervical and dorsal vertebra) somewhat lower. Paddles (fig. 23), 

 generally narrower, with five or six longitudinal rows of bones in 

 middle of pectoral, and four or five in pelvic. In pelvic paddle 

 anterior border of tibiale and adjacent tarsale of second row notched • 

 and when there are five longitudinal rows of oblong bones in middle 

 of pectoral paddle those of first row nearly square (instead of 

 oblong), with their anterior border notched. Vascular foramina in 

 centre of bones of paddles large and distinct ! . Clavicles more 



1 Trans. Geol. Soc. ser. 2, vol. i. pt. I, p. 108 (1822). 



2 Memoirs on Ichthyosauri kc. pi. xviii. (18.'J4). 



:| This character was pointed out by Hawkins, and although its validit \ vras 

 discredited by Owen, it appears to be distinctive. 



