BRITISH FOSSIL REPTILES. 123 



is admirably worked out, and part of the vertebral column. 

 Besides the character expressed in the specific name proposed 

 by the accomplished Mineralogist and Paleeontologist, whose 

 name is associated with the genus, of which the present'species 

 forms so interesting an addition ; the foramen parietale appears 

 to be unusually large ; and the articular surfaces of the bodies 

 of the vertebrae present a flattened circumference. 

 Ichthyosaurus latimaniis, O. 



This species resembles the Ichthyosaurus cnmmujiis in the 

 ventricose, subobtuse character of the teeth, of which I have 

 counted twenty-nine on one side of both jaws. 



The articular surfaces of the vertebrae are only concave in the 

 middle third part of their transverse diameter ; the rest of the 

 surface to the circumference is flat. They are stouter in the 

 pelvic region than in the Ich. communis. The chief difference 

 between this species and the Ich. communis obtains in the re- 

 lative sizes of their anterior paddles. In an Ich. latimanus 

 of six feet ten inches in length, and an Ich. communis five 

 feet two inches in length, the following were the respective 

 dimensions of the bones of the anterior paddle : 



Icli. latimanus. Ich. communis. 

 Inch. Lines. Inch. Lines. 



Scapula, length of 3 4 3 



, breadth of humeral end .18 13 



Antibrachial bones, breadth of . 2 5 17 



Length of entire paddle ... 7 6 50 



Breadth of ditto 3 6 2 8 



Coracoid, intero-posterior diameter 3 8 2 4 



, transverse diameter ..32 20 



The clavicle was also proportionally powerful in the Ich. 

 grandipes, and measured six inches eight lines in length. 



The head is relatively shorter in the Ich. latimanus than in the 

 Ich. communis ; in the present specimen the lower jaw mea- 

 sures one foot four inches, while in the Ich. communis above 

 cited the lower jaw measured one foot five inches. 



In the nearly complete but dislocated skeleton in the mu- 

 seum of the Philosophical Institution at Bristol, on which the 

 present species is founded, I counted 114 vertebrae; the ter- 

 minal vertebrae of the tail presenting the compressed character 

 indicative, as before noticed, of the former existence of a ver- 

 tical tegumentary fin. Parts of the carbonized integument are 

 preserved on the slab of lias on which this interesting fossil 

 reposes ; there is a broad patch about four inches beyond the 

 last caudal vertebrae, being the first evidence I have yet met 

 with of the actual presence of the caudal fin. The traces of 

 tegument in the abdominal region are smoother than those 

 figured in Dr. Buckland's Bridgewater Treatise. 



