408 DIOTOCARDIA— RHIPIDOGLOSSA chap. 



Fam. 1. Cocculinidae. — A single cervical ctenidium, foot 

 broad, no eyes, shell patelliform, with caducous spire. Single 

 genus, Cocculina. Deep water. 



Fam. 2. Stomatellidae. — A single (left) ctenidium, front third 

 free, shell nacreous, spiral or patelliform, depressed, last whorl 



large. Jurassic . Genero,: Stomatella (^suhg. Si/naptocochlea, 



Wiphonia)^ shell depressed, spirally ribbed, spire short, operculum 

 present ; Phaneta^ fluviatile only, shell trochiform, imperforate, 

 last whorl keeled, sinuate in front ; Stomatia^ spire short, surface 

 tubercled or keeled, no operculum : G-ena, shell haliotis-shaped, 

 surface smooth, aperture very large : Broderipia^ shell patelli- 

 form, spiral apex often lost. 



Fam. 3. Cyclostrematidae. — Tentacles ciliated, thread-like, 

 snout bilobed, foot truncated in front, angles produced into a 

 filament, shell depressed, umbilicated, not nacreous. Eocene 



. Principal genera : Cyclostrema^ Teinostoma, Vitrinella. . 



Fam. 4. Liotiidae. — Epipodial line with a lobe behind each 

 eye-peduncle, shell solid, trochiform, longitudinally ribbed or 

 trellised, aperture round, operculum multispiral, hispid, corneous, 



with a calcareous layer. Silurian . Principal genera: 



Liotia^ Craspedo stoma (Silurian), Crossostoma (Jurassic). 



Fam. 5. Trochidae. — Snout short, broad, frontal lobes often 

 present, epipodial line furnished with cirrhi; shell nacreous, I 

 variously spiral, operculum corneous, multispiral, nucleus central • 



(Fig. 182, p. 268). Silurian . 



(i.) Trochinae. — Frontal lobes present, 

 lateral teeth (= side centrals) 5 only, , 

 no jaws, peristome incomplete. Prin- I 

 cipal genera: Trochus (subg. Cardi- 

 nalia^ Tectus^ Infundibidum, Clan- 

 culus)^ Monodonta (subg. Biloma)^ 

 Fig. 270. — Monodonta canali- Cantharidus (subg. Bankivia, Tlia- 



fera Lam., New Ireland l^^tio), Gaza (subg. MicrogaZO), Cal- 

 (After Quoy and Gaimard.) x^ 7 . Tyn ^•- \ 



logaza^ Bemoix, C/ilorostoma. (ii.) 

 G-ihhulinae. — Frontal lobes and jaws present, laterals often 

 more than 5, peristome incomplete. Principal genera: Gih- 

 hula (subg. Monilia^ Aphanotrochus, Enida)^ Minolia^ Cir cuius, 

 Trochiscus^ IJvona, Photimda, Margarita^ Solariella, Calli- 

 ostoma. Turcica^ Basilissa, Euchelus (subg. Olivia^ Perrinia). 

 (iii.) Belphinulinae. — No frontal lobes, jaws present; shell solid, 



