192 MANUAL OF THE MOLLUSC A. 



Animal oblong or elongated ; tentacles laminated, non-retractile, sheath- 

 less ; head-veil bordered with tubercles or tentacular processes ; gills with 2 

 or more lateral appendages. (A. and H.) 



Distr. Norway, 5 sp. Brit. Red Sea. Within tide-marks and in deep 

 water on corallines. The spawn is strap -shaped, and coiled on stones, in 

 July and August. P. ocellata (Plocamophoms, Riippell) has the cephalic 

 tentacles branched. 



ID ALIA, Leuckart. 



Etym. Idalia, Venus, from Mt. Idalium in Cyprus. 



Syn. Euplocamus, Phil. Peplidium (Maderse) Lowe. 



Ex. I. aspersa, PL XIII. fig. 6. Coralline zone. 



Animal broadly oblong, nearly smooth, tentacles clavate or linear, with 

 filaments at their base ; head slightly lobed at the sides ; mantle very small, 

 margined with filaments; lingual teeth 2.0.2. 



Distr. Norway, Brit. (4 sp.) Medit. Madeira. 



ANCULA, Loven. 



Syn. Miranda, A. and H. Type, A. cristata, Alder. 



Animal slender, elongated; mantle entirely adnate, ornamented with 

 simple filaments ; tentacles clavate, laminated ; with filiform appendages at 

 their base ; labial veil produced on each side. 



Distr. Norway, Brit. Lon. ^ inch. 



CERATOSOMA (Gray), A. Adams. 



Etym. Ceratois, horned, soma, body. Type, C. cornigerum, Ad. 



Animal oblong, narrow, with two large and prominent horn-like pro- 

 cesses on the posterior part of the back, behind the gills ; gills 5, bipinnate ; 

 dorsal tentacles clavate, laminated, rising from rounded tubercles, non- 

 retractile ; head with short lateral processes : foot narrow. 



Distr. Sooloo sea. (A. Adams.) 



FAMILY VII. TRITONIAD.E. 



Animal with laminated, plumose, or papillose gills, arranged along the 

 sides of the back ; tentacles retractile into sheaths ; lingual membrane with 

 1 central and numerous lateral teeth ; orifices on the right side. 



TRITONIA, Cuvier. 



Ex. T. plebeia, PL XIII. fig. 7. 



Animal elongated ; tentacles with branched filaments ; veil tuberculated 

 or digitated ; gills in single series on a ridge down each side of the back ; 

 mouth armed with horny jaws; stomach simple; liver compact. 



Listr. Norway, Brit. Under stones at low-water, ^5 fm. F. Hom- 

 bergii, Cuv. found on the scallop -banks, attains a length exceeding 6 inches. 



