v. 



Tehcnnophoms Carolinensis. 411 



LhnacklcB of the United States,* to propose for it a new 

 genus under the designation of Tebennophorus. For the 

 external characters of the animal, which is the subject of this 

 paper, reference is made to Dr. Binney's description, and 

 accurate figures of it may be found in his forth-coming volume 

 on the terrestrial Mollusks. The object of this paper is to 

 elucidate its anatomy, with a view of determining how far its 

 structure differs from that of the other jrenera of the faniilv. 



The dorsal shield or cuirass, excepting as regards its size, 

 in its external characters resembles that of the different 

 species of Limctx. On making a longitudinal incision, how- 

 ever, along the middle of the back, as in PL xxii. fig. 1, there 

 is found to exist, between it and the viscera, a large cavity, 

 occupying the whole extent of the dorsal and lateral regions 

 this cavity has no communication with the respiratory sack 

 no air passing into it when the latter was forcibly distended. 

 It did not communicate externally with the air, being pro- 

 tected from it at all parts by the shield, except under the 

 anterior extremity of the latter, where it was covered only 

 by a thin membrane. The whole of its internal surface is 

 lined by a thin, smooth, delicate membrane enveloping the 

 viscera, so as to unite them into a single mass, and from them 

 it is reflected upon the tegumentary parietes, like the peri- 

 toneum of the higher animals. In the different species of the 

 genus Limax the membrane, by which the different viscera 

 are invested, is attached by a loose cellular tissue to the pari- 

 etes, so that no similar cavity can be said to exist. In Teben- 

 nophorus no cavity exists in the cuirass similar to that contain- 

 ing the calcareous body in the Limnces. 



The different organs are represented, in fig. 1, as they 

 appear when exposed by laying open the cavity which has 

 just been described. At the anterior extremity is seen the 

 buccal pouch, from the centre of which commences the oeso- 

 phagus, and on each side the upper tentacles : a, is the respira- 

 tory sack ; b, a part of the viscera ; c c, the liver ; d, testis ; 

 //, integuments. 



* See the present volume of this Joiirnal, page 163. 



