g6 FAMILIES AND GENERA. 



Aporrhaidse. (PROSOBRANCHIATA.) Plate xxv. 

 Aporrhais, 455, 456. 



Areadae. (FILIBRANCHIATA.) Plate i. 

 Ana, hinge straight, 11-15. 



Pectunculus, shell orbicular, nearly equilateral ; hinge semi- 

 circular, striated ligamental area, 16. 



Limopsis, hinge with two curved series of transverse teeth and 

 triangular cartridge pit in the middle, 17, 18. 



Assimineidse. (PROSOBRANCHIATA.) Plate xxiv. 

 Assiminea, 432, 433. 



Astartidse. (EULAMELLIBRANCHIATA.) Plate v. 

 Astarte, 50-52. 



AuriCUlidse. (PULMONATA.) Plate xvii. 



Carychium, umbilicus an oblique sttt, 201. 

 Melampus, no umbilicus, 202, 203. 



AviCUlidse. (PSEUDOLAMELLIBRANCHIATA.) Plate iii. 

 Avicula, shell winged ; hinge with teeth, 30. 

 Pinna, shell triangular, not winged ; hinge without teeth, 31. 



Bueeinidse. (PROSOBRANCHIATA.) Plate xxvii. 



Buccinum, coarsely grooved, operculum lamellar, with nucleus on 



outer side of mouth, 517, 518. 

 Buccinopsis, finely striated, operculum with nucleus on inner side 



of mouth, 519. 



Bullidse. (OPISTHOBRANCHIATA.) Plate xxx. 



Acera, mouth extending nearly the length of the shell, 568. 

 Bulla, mouth extending the whole length of the shell, 565-567. 



CDBCidse. (PROSOBRANCHIATA.) Plate xxv. 

 Ccscum, 453, 454. 



Capulidse. (PROSOBRANCHIATA.) Plate xxiii. 



Capulus, shell cap-shaped, no internal plate, 382. 

 Calyptrcea, shell conical, with internal plate, 383. 

 Crepidula, shell slipper-shaped, with septum covering half the 

 mouth, 384. 



Cardiidse. (EULAMELLIBRANCHIATA.) Plate xi. 

 Cardium, 129-138. 



