MUSEUM OF COMPARATIVE ZOOLOGY. 25 



Family RISSOID^. 



Genus RISSOA Freminville. 

 Rissoa precipitata Dall. 

 Risaoa acuticostata Dall. 



Genus RISSOINA Orbignt. 

 Rissoina laevigata C. B. Adams. 

 Rissoina albida C. B. Adams. 

 Rissoina decussata Montagu.* 

 Rissoina Chesnelii Michaud. 



Genus BENTHONELLA Dall. 

 Benthonella gaza Dall.* 

 Benthonella Fischeri Dall* 

 Benthonella nisonis Dall.* 



Family CALYPTR^EID^E. 



Genus MITRULARIA Schumacher. 

 Mitrularia equestris Linne. 



Genus CRUCIBULUM Schumacher. 

 Crucibulum auricula Gmelin. 



Section DISPOT^EA Say. 

 Crucibulum striatum Say. 



Genus CALYPTR^EA Lamarck. 

 Calyptraea Candeana Orbigny. 



Genus CREPIDULA Lamarck. 

 Section J AN AC US Morch. 

 Crepidula protea Orbigny. 



Section SANDALIUM Schumacher. 

 Crepidula aculeata Gmelin. 



Family CAPULID^. 

 Genus CAPULUS Montfort. 



Section KREBSIA Morch. 

 Capulus intortus Lamarck. 



Section HYALORISIA Dall. 

 Capulus galea Dall. 



