80 REPORT — 1841. 



being thicker, rectangular, and having the outer surface impressed with cir- 

 cular pits or indentations from three to four lines in diameter, which are not 

 confluent, but separated. 



The median dorsal scutes of the Whitby specimen are nearly square, 

 having the longer diameter, about three inches and a half across, placed trans- 

 verse to the axis of the body, and with the outer margin slightly rounded. 

 Each of these scutes is traversed, as in the Teleosaurus priscus, by a longi- 

 tudinal ridge, which is less developed than in the Gavials. The median dor- 

 sal scutes of the Teleosauri Cadomensis and priscus appear to differ from 

 those of the Teleosaurus Chapmanni in being more oblong transversely, and 

 with the posterior and lateral margins rounded off. Cuvier does-pot allude 

 to the cai'inated character of these plates in the Caen species. 



The lateral and ventral scutes of the Teleosaurus Chapmanni are more per.r- 

 feet squares than those next the spine, but differ less in form and size fro.m 

 them, than in the Caen Teleosaur. They are marked externally by the same 

 impressed pattern, but are not carinated. The median abdominal scutes are 

 not opposite but alternate ; their median margins are rounded ofl^, or slightly 

 angular ; and, while the anterior part of that margin is overlapped by the 

 posterior half of the opposite scute, in advance, the posterior half overlaps 

 the succeeding scutum of the opposite side. The verticillate cuirass of these 

 ancient Crocodiles is thus securely braced round the trunk by this inter- 

 locking of the inferior extremities of each ring of scutes, whilst the imbri- 

 cated arrangement would allow of a certain sliding motion of the rings upon 

 each other sufficient for the expansion qf the chest in breathing. The scutes 

 in the fine specimen in the Whitby Museum measure about five lines in 

 thickness, but are thinned off at the edge. 



Having now detailed the anatomical particulars which a study of the mag- 

 nificent and unique skeleton of the Teleosaurus, in the museum at Whitby, 

 has enabled me to add to the previous descriptions, by Cuvier and other ana- 

 tomists, of the osteological structure of this extinct Crocodilian genus, I next 

 proceed to notice the principal examples of the same genus which are preserved 

 in other collections of British Fossil Reptiles. 



The first of these is a fine skull of the same species of Teleosaurus, and 

 from the same lias beds near Whitby, in the museum of Mr. Ripley of that 

 town : — 



Feet. Inches. 



The length of the entire skull is 2 9 



From the angle to the beginning of the long symphysis of 



the lower jaw 1 3 



Breadth of the lower jaw at the posterior commencement 



of symphysis 2^ 



Breadth of the extremity of the lower jaw 1 



The extremity of the upper jaw well exhibits in this specimen the charac- 

 teristic generic modification of its infundibuliform expansion, supporting the 

 terminal nostrils, and resembling the extremity of the elephant's proboscis, 

 wanting the digital process. 



This cranium also clearly exhibits the specific charactei's by which the 

 Teleosaurus Chapmanni of the Yorkshire lias differs from the Teleosaums 

 Cadomensis of the Caen oolite, viz. the greater antero-posterior extent of the 

 upper temporal openings as compared with their transverse diameter in the 

 Teleosaurus Chapmanni; the similar but slighter difference in the form of 

 the orbits, the greater breadth of tiie interorbital space, which slightly ex- 

 ceeds the transverse diameter of the orbit instead of falling short of that 

 diameter, as in the Teleosaurus Cadomensis. 



