41 



3. Description of the Animals andTeeth ofTylodina and 



OTHER GeNERA OF GaSTEROPODOUS MoLLTJSCA. 



By Dr. John Edward Gray, F.R.S., V.P.Z.S., P.B.S. etc. 



In the following paper I forward the description of the animal 

 and the teeth of several genera of Mollusca which have not yet been 

 recorded. It is interesting to find that the examination of the teeth 

 justifies the position which was theoretically assumed for the genera 

 in the different faraihes before their teeth were known. 



A. Proboscidifera Hamiglossa. 

 Fam. MuRiciD^. 



Fusus PALLIDUS ("F. turbinelloides=:Pį/rula lignaria, Reeve"). 



The proboscis elongate, cyhndrical, subclavate, entirelv retractile ; 

 the lingual membrane elongate, narrow, yellow ; teeth in three 

 longitndinal series, 1 • 1 • 1, the centrai transparent, provided with a 

 rounded front edge, armed with three rather elongate, conical, sub- 

 equal denticles ; the lateral teeth yellow, versatile, straight, with two 

 compressed arched processes, the terminai one largest, the basai 

 rather smaller, and with a small tooth on its outer edge. The oper- 

 culum is horny, thick, ovate, subtrigonal, anuular, as large as the 

 mouth of the shell ; the apex blunt, rather worn ; the nucleus api- 

 cal, scar large oblong, with a thick callous exterior margin. 



Typhis tetrapterus. 



Operculum horny, ovate, blunt, laminar ; nucleus anterior apical, 

 as large as the mouth of the shell, rather broader behind. 



PiSANiA ELEGANS. Panama. 



The animal pale brown (in spirits) ; the foot folded up and across 

 behind, and together longitudinally in front, leaving a jL-shaped 

 groove ; tentacles very small ; proboscis elongate, thick, clavate, en- 

 tirely retractile ; lingual membrane elongate, thin ; teeth in three 

 longitudinal rows, 1 • 1 • 1, centrai far apart from each other, and the 

 lateral teeth, lunate, with a slightly denticidated, nearly straight, 

 front edge, and a rather strong concave tooth at each end ; lateral 

 teeth versatile, large, with a nearly equal basai and apical, conical, 

 curved process. Malė organ slender, elongate, tapering, yelIow, 

 compressed. Operculum ovate, acute, thick, horny, annular, nucleus 

 apical. 



Triumphis distorta. Panama. 



Lingual membrane elongate ; teeth in three longitudinal series, 

 r r 1 ; centrai teeth very small, far apart ; lateral large, versatile, 

 with tsvo basai uneąual, and one larger terminai curved process. 

 Operculum ovate, acute, very thick. 



