OF MOLLUSCA. 



121 



Pilidium commodum of Middendorff (Reise, ii. 214. t. 17. f. 4, 1 1) 

 appears to be a species of Velutina, or perhaps a subgenus allied to 

 it, rather than belonging to this Family. 



2. Hipponyx. 



The foot secreting a testaceous valve, which is adherent by its 

 outer surface to marine bodies. 



1. H. radiata, t. 130. f. 6. 



2. H. foliata, t. 130. f. 5. 



The rostrum of Hipponyx subrufa rather elongate, depressed, 

 brown, end transverse, lozenge-shaped. Mouth oblong, erect. Ten- 

 tacles subulate, white, on the sides of the base of the rostrum, and 

 with a belt continued over the upper surface of its base. Gills 

 in a series of elongated filaments attached to the inner side of the 

 mantle, forming an oblique line over the head. 



Hipponyx barbata lives on stones and shells near low water mark, 

 Panama. — C. B. Adams. 



Hipponyx granulat a (Proc. Zool. Soc. 1853, 176. t. 20. f. 3) lives 

 attached to the spines of a Cidaris on the west coast of Africa ; it 

 forms an oblong testaceous plate, with thickened edges, and the 

 margin of the aperture is adapted to the semicylindrical surface of 

 attachment. At first sight, this species has very much the appear- 

 ance of a Pedicularia. — Adams. 



** Foot forming a deep concavity in the surface of shells, with a 

 horse-shoe-shaped ridge in the centre. 



3. Amalthea. 



1. A. conica, t. 130. f. 7. 



In the young state, the shells of Amalthea conica are subspiral, of 

 one and a half or two whorls, and transparent brown. Immediately 

 they are hatched, they become conical and straight, and at length 

 they thicken and the subspiral apex is worn away. 



Fam. XXII. VANICOROID^l. 



Shell semiovate, spiral. Mouth contracted. Muzzle produced, 

 conical, wrinkled. Jaws two, horny, flat. Lingual membrane 

 broad, short, " with two series of teeth, and prolonged behind." Ten- 

 tacles prismate, fusiform, pointed ; eyes on outer side of their base. 

 Foot small, circular, produced in front, with a dilated membranaceous 

 expansion on each side. Operculum horny, thin, ovate, subspiral, 

 of very few indistinct whorls, striated. 



