122 



MANUAL OF THE MOLLUSCA. 



Trivia, Gray. C. eiiropeea, PI. VII., fig. 23 ; fig. 76, and 15, B. 

 Small shells ^\itli striae extending over the back. (U/icini ; 1st denticulate 

 2, 3, simple.) 



Di^tr., 30 sp. Greenland, Brit., TV. Indies, Cape, Australia, Pacific, TV. 

 AniOTca. 



Erato, Risso. 



JSti/m., Erato, the muse of love-songs and mimicry. T?/pe, E. he\-is. 

 PI. Vli., fig. 24. 



Shell minute ; Kke marginella ; lips minutely crenulated. Animal, like 

 trieia. 



Disfr., 8 sp. Brit., Medit., TV. Indies, China. 



Fossil, 2 sp. jMiocene — . France, Brit. (Crag.) 



OvuLUM, Lam. 



Ef^/n., dimunitive of ovum, an egg. S//??., amphiceras, Gronov. 



Types, O. ovum, pi. VII., fig. 25. 0. gibhosa and verrucosa. 



^lell, lilce cj/prcea; inner lip smooth. 



Bistr., 36 sp. T\"ann seas. T\^. Indies, Brit., Medit. China, TV. America. 



Fossil, 11 sp. Eocene — . France, &c. 



Suh-gemis, calpiirna, Leach. 0. volva ("The weaver's shuttle"). Apei-- 

 tiu'e produced into a long canal at each end. Foot narrow, adapted for 

 walkiug on the round stems of the gorgonicB, &c., on which it feeds. C. 

 patula inhabits the S. coast of Britain, it is very thin, and has a sharp out^er 

 lip. 



SECTION B. HoLOSTOMATA. Sea-SnaHs. 



Shell, spiral or limpet shaped ; rarely tubiolar or multivalve : margin of 

 the aperiure entire. Operculum, horny or shelly, usually spii-al. 



Animal with a short non-retractile muzzle ; respiratory siphon wanting, 

 or fonned by a lobe developed fi-om the neck (fig. Gl), gills pectinated or 

 plume-like, i)laced obliquely across the back, or attached to the right side of 

 the neck ; neck and sides fi-equently ornamented with lappets and tentacular 

 filaments. Marine or fresh- water. Mostly phytophagous.* 



FAMILY I. NATICID.E. 



Shell, globular, few-whiiied ; spii-e small, obtuse ; aperture, senii-lmiai' ; 

 lip, acute ; pillar often callous, 



Afiimal, with a long retractile proboscis ; lingual ribbon linear ; rachis, 1 

 toothed ; nncitii, 3 (similar to trivia, fig. 15, B.) ; foot veiy large ; mantle-lobes 

 largely developed, hiding more or less of the shell. Species aU marine. 



* These " sections" are not very satisfactory, but they are better than any others 

 yet proposed, and they are convenient, on account of the great extent of the order 

 proso-branchiata. Natica and scalaria have a retractile proboscis. Pirena has a 

 notched aperture, and aperrhais, a canal. 



