with a revision of the Limnceidce of Authors. 357 



Family CHILINIDyE. Dall. 

 Tentacles flattened. Mantle with a rhombiforra lobe cover- 

 ing the opening of the pulmonic chamber. Shell dextral, 

 columella plicate. Genitalia on the right side. Lateral teeth 

 uniformly comb-like, with the bases prolonged before the inser- 

 tion of the cusps. No accessory simple teeth. No jaw. Cen- 

 tral tooth as in Physa. 



Genus Chilina. Gray. 1840. 

 Type C.fiuctuosa. 



Sub-genus Chilina. 

 Shell with a short blunt spire, smooth epidermis, usually 

 marked with bands of color and of more or less solid structure. 

 Type Chilina ampxdlacea. Sby. 



Sub-genus Pseudochilina. Dall. 



Shell thin, covered with a rough fibrous epidermis ; spire 

 elevated, acute. 



Type Pseudochilina limnaformis n. s. 



Testa acuto-conica, suhtenuis ; spira elevata, ad apicem acu- 

 minata / suturis subimpressh, anfr. VI. ; apertura elongata ; 

 labro aouto / columella lata, plica valde ?nunita, dente incon- 

 spicuo arrnata • epidermide aspera, semifbrosa, fusca. 



Lon. 0.67, lat. 0.35. in. Defl. 58°. 



Smithsonian Cabinet No. 5,908. Chili. Commodore Aulick, 

 coll. 



The curious epidermis and broad plicate columella alone 

 distinguish this singular shell from a Zimncea. 



NOTES. 



The figures given by H. & A. Adams, of Amphipeplea arc 

 not good. Those of Moquin Tandon are much better. 



Most of the figures of dentition of the fresh-water species 

 given by Binney in the Land and Fr. Water Shells of N. Am. 

 Part II., are far from good. 



Some authors state that the lateral jaws of Ancylus are not 

 continuous with the buccal plate. I have followed Moquin 



