396 MOLLUSCA. 



Ampullaria, Cydoplwrus, Ac.icula, some Cerifhiidae, etc.). Radula 

 with central tooth single or absent. 



The ctenidium, auricle, and kidney of one (right) side are absent, 

 and the ventricle is not traversed by the rectum. The ctenidium is 

 monopectinate (Fig. 280), and attached to the mantle by its whole 

 length. The kidney opens by a slit, exceptionally by a ureter 

 (Paludina, Cydophorus, Valvata), and never receives the generative 

 products. A penis is generally present, and the gonad has its own 

 duct and opening. 



Tribe 1. PTENOGLOSSA. 



Without siphon. Peristome entire. Mouth with proboscis or snout. Penis 

 absent. Radula without median tooth, with numerous lateral hooks (oo . 0. oo ). 



Fam. 1. lanthinidae. Snout prominent, blunt; tentacles bifid; no eyes; 

 shell thin, spiral, without operculum. Foot small, secreting a float, to which 

 the eggs are attached. Pelagic, carnivorous. lanthina Lam.; /. fragilis L. , 

 Atlantic and Med.; Rccluzia Pet. 



Fam. 2. Solariidae. Shell flattened, with a large umbilicus which extends 

 to summit of spire. Head short, proboscis long; foot small. Tentacles slit 

 along their whole length. Solarium Lam. Stair-case shell. 



Fam. 3. Scalariidae. Shell turriculated ; a small siphon ; foot and proboscis 

 .short. The animal secretes a purple liquid when molested. Carnivorous. 

 Scalar-ia Lam., wentle-trap. 



Tribe 2. RACHIGLOSSA. 



With long proboscis, evaginable from the base. Radula with at most three 

 teeth in each row, a cusped median tooth, and a cusped lateral on each side, 

 which may be absent ; marginals absent (Fig. 293 C). All possess a siphon and 

 are predatory. 



Fam. 1. Muricidae. Eyes at the base of the tentacles; foot truncated; an 

 anal gland. Murex L. The Ancients obtained their purple from species of 

 Murex; it is secreted by the anal gland. M. erinaceus, sting- winkle, English 

 Channel ; M. trunculus L. Heaps of shells of this species still to be seen on 

 the Tyrian shore. Purpura Brug. ; P. lapillus L., destructive to mussel beds; 

 Trophon Montf. ; Urosalpinx Stimpson. 



Fam. 2. Coralliophilidae. Radula absent. Inhabits coral reefs. Magilus 

 Montf.; Lcptoconclius Rtipp. ; Coralliophila H. and A. Adams. 



Fam. 3. Columbellidae. t.'olumbella, Lam. 



Fam. 4. Nassidae. Foot long, broad, often with terminal appendage; 

 siphon long; eyes on outer base of tentacles; central tooth of radula arched, 

 mnlticusped, laterals bicuspid with small denticles between the cusps; shell 

 buccinoid. Nassa Lam.; N. reticulata L., dog- whelk, common on English 

 coasts at low water ; Canidia Adams ; Cyclonassa Swainson ; Bullia Gray. 



Fam. 5. Buccinidae. Eyes at base of tentacles; foot large; proboscis long. 

 Central tooth of radula with 5-7 cusps, laterals bi- or tri-cusped. Shell thick, 

 covered with periostracum ; canal of varying length ; operculum corneous. 

 Buecinum L., whelk; Chrysodomus Swainson. 



The Haliidae (Halia Risso) are allied here. 



