PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 71 



When received at the museum the specimen was attached by matrix 

 to the lower end of the femur of Mastodon ainericavMS, No. 11,185, 

 U.S.N.M., a partial skeleton, including the skull, tusks, and lower 

 jaw. 



The carapace, except for the loss of a small area on the right hinder 

 side, is uncrushed and in an excellent state of preservation. All 



of the bones are solidly 

 united, so that none of 

 their sutural contacts can 

 now be determined; 

 hence the form of the 

 individual bones is un- 

 known. 



The bone of the cara- 

 pace is somewhat thick- 

 ened when contrasted 

 with the very thin shells 

 of Terrapene innoxia 

 Hay and T. formosa 

 Hay ^ from these same 

 deposits. 



The shell is relatively 

 long and narrow when 

 contrasted with the 

 loiown species of the 

 genus, highest at the 

 center and sloping off 

 more rapidly behind 

 than in front. It is 

 estimated that the com- 

 plete carapace had a 

 greatest length, taken in 

 a straight line at the 

 center, of 200 mm. and 

 a greatest width of 132 

 mm. These measurements show the width to be 0.66 of the length, 

 whereas in the living T. Carolina, as given by Hay," the ratio is 0.86, 

 and in the extinct species, T. formosa, T. innoxia, and T. canaliculata, 

 is 0.72, 0.68, and 0.70, respectively. 



The nuchal border is broadly and shallowly excavated, resembling 

 in this respect adult specimens of T. major. The borders of the 



Fio. 1. — Carapace of Terrapene singletoni. No. 

 11,181, U.S.N.M. Ttpe V. S. 1, first vertebral 



SCUTE ; V. S. 4, FOURTH VERTEBRAL SCUTE. ONB- 

 HALF NATURAL SIZE 



1 Hay, O. P., Ann. Rept. Florida State Geol. Survey, 1916, pp. 57-58 and 61-64, pi. 4, 

 fig. 3 ; pi. 6, figs. 3 and 4. 

 - Idem. i>. 57. 



