NATURAL SCIENCES OF PHILADELPHIA. 125 



plates of the sides, where, instead of being on the centre, they are situated on 

 the inner margins. Although the specimen is very young less than an inch in 

 length the spots are already wanting on some of the plates, probably vanish- 

 ing with age. 



This species is deeply interesting, and especially so to the members of this 

 Society, on account of its very limited geographical distribution, being con- 

 fined probably to a radius of about 50 miles from the city of Philadelphia. 

 Probably it is in a slow progress towards extinction, and an eutire disappear- 

 ance from the earth ; and hence it is plainly important to science that there 

 should be an immediate investigation of the exact boundaries of its distribu- 

 tion, so that hereafter from time to time its course towards an ultimate anni- 

 hilation may be clearly seen. 



Besides being, as already known, one of the smallest of turtles rather 

 smaller than the Nanemys guttata it is quiet and mild in its habits, not at all 

 ferocious, though its food consists chiefly of insects, and in a smaller degree 

 of vegetation. It frequents meadows in the vicinity of streams. As the culti- 

 vation of the land becomes more complete, its haunts will be diminished, its 

 food lessened, and its numbers decreased. 



While this genus is confined to a small distance of the borders of the Dela- 

 ware River, the grea,t confluent of the Delaware Bay, it is remarkable that 

 a species of another genus the Ptychemys rugosa is confined to the con- 

 fluents of the nearly adjoining Chesapeake Bay. 



June 18 th. 



Vice-President Bridges in the Chair. 



Twenty-two members present. 



An announcement was made of the death of Franeis Peters, Esq., a 

 member of the Academy, at Paris, France, on the 19th of May. 



June 25th. 



Vice-President Bridges in the Chair. 



Twenty-two members present. 



On report of the respective Committees, the following were ordered 

 to be published in the Proceedings : 



Descriptions of new species of Cyrena, Corbicula and Sphserium. 

 BY TEMPLE PRIME. 



1. Cyrena Cyp r inaefo r mis Prime. C. testa ovato-suborbiculari, valde 

 inaequilaterali, turgida, crassa, epiderniide viridi-nigresceute vestita ; umboni- 

 bns minimis, oblique antice curvatis, acutis, parum prominentibus ; latere 

 antico brevi, rotundato, postice subtruncato ; lamina cardinali lata ; dentibus 

 cardinalibus elongatis, prominentibus, apice profunde furcatis ; dentibus late- 

 ralibus brevibus, antico crasso, conico. 



Long. 91 ; lat. 85 ; diam. 60 mill. 



Hab. Northern Australia. (Collect. Cuming et Prime.) 



This large species is somewhat allied to the Cyrena Cyprinoides Quoy ; 



it is, however, less triangular in its general appearance, and its beaks are less 



inflated. 



2. Cyrena 1 aev is Prime. C. testa orbicmlato-trigona, depressiuscula, inae- 

 quilaterali, tenui, minuta ; epilermide viridi-glaucescente vestita ; regulari- 

 ter transversiin striata ; latere antico obtuso, margine superiore postico con- 



1861.] 



