240 Sellards — \< w Tortoise and a Supplementary Note. 



cies. These plates are heavy deeply pitted pieces of hone, the 

 largest of which measure 100 by 130 mm in size and are 16 mm 

 thick. A vertebra, the centrum of which is 70""" long by 50 nim 

 wide, has been obtained from this locality and presumably 

 represents this species. This vertebra is probably the seventh 

 of the series. 



The skull of this extinct gavial is somewhat more massive 

 than is that of the modern species. Thus a jaw of T. sc/degeli, 

 the symphysis of which measures 610 mm , lias a width at the 

 forward end of the splenials of 170"" n , the width being more 

 than one-fourth the length. In the recent species the width 

 of the jaw at the same place is contained in the length 6J times, 

 thus indicating a more narrow jaw and skull. The symphysis 

 of the jaw of T. schlegeli begins opposite the fourteenth tooth, 

 while in T. americana the symphysis as previously stated 

 begins opposite the eleventh or twelfth tooth. In the propor- 

 tionate length of the symphysis to the jaw as a whole, how- 

 ever, as well as in the extent to which the splenials enter into 

 the symphysis, the two species do not differ to any great 

 extent. 



The body proportions of this gavial probably do not differ 

 greatly from those of the existing species of the genus, and 

 hence by comparative measurements it is possible to form a 

 reasonably close estimate of the size of this extinct animal. 

 Upon comparing the modern species, Tomistoma schlegeli, it 

 is found that in an individual, the full length of the body of 

 which is 9 feet and 7 inches, the lower jaw measures 2 feet 

 and 2 inches.* Assuming that a somewhat similar proportion 

 holds between the length of the jaw and of the body of T. 

 americana, and applying these measurements, the conclusion is 

 reached that large individuals of the Florida gavial, the jaw of 

 which exceeds 4 feet, attain a length of 18 or 19 feet, and 

 hence were somewhat larger than the existing gavial of this 

 genus which seldom exceeds 15 feet in length. 



* Measurements from the recent skeleton kindly supplied by Geo. M. Ward 

 of the Ward Natural Science Establishment. 



