FAMILIES AND GENERA. 103 



Polyeeridse. (OPISTHOBRANCHIATA.) Plate xxxiii. 



Polycera, dorsal tentacles laminated and non-retractile, 604. 

 SEgirus, dorsal tentacles linear and retractile, oral indistinct, 605. 

 Triopa, dorsal tentacles laminated and retractile, oral cylindrical, 



606. 



Thecaccra, dorsal tentacles laminated and retractile, oral none, 607. 

 Crimora, dorsal tentacles laminated and retractile, oral tuber- 

 cular, 608. 



PoromyidSB. (EULAMELLIBRANCHIATA.) Plate xv. 

 Poromya, shell roundish oval, 179. 



Neara, shell fig-shaped, posterior end being twisted and produced, 

 180-183. 



Psammobiidse. (EULAMELLIBRANCHIATA.) Plate xii. 

 Psammobia, 139-142. 



PupidSB (PULMON.ATA). Plate xx. 



Pupa, mouth oval or lunate, 288-291. 



Vertigo, mouth more or less angular, 292-302. 



Balca, shell sinistral, mouth ovate, 303. 



Clausilia, shell sinistral, mouth with clausilium, 304-309. 



Cochlicopa, mouth pyriform, 310, 311. 



PyramidellidSB. (PROSOBRANCHIATA.) Plate xxvi. 

 Odostomia 468-502. 



RisSOidcG (PROSOBRANCHIATA.) Plate xxiv. 

 Barleeia, colour red, 425. 

 Rissoa, colour not red, 400-424. 



Runeinidse. (OPISTHOBRANCHIATA.) Plate xxx. 

 Runcina, 582. 



ScalariidSB. (PROSOBRANCHIATA.) Plate xxii. 



Scalaria, shell turreted, longitudinally ridged, mouth almost 

 round, 360-364. 



Aclis, shell pyramidal, smooth or sculptured, mouth oval, outer 

 lip thin, 365-369. 



Seaphandridse. (OPISTHOBRANCHIATA.) Plate xxx. 

 Scaphander, shell pear-shaped or oval, 558, 559. 

 Cylichna, shell cylindrical, 560-564. 



