134 mrroNYX. 



Subfamily Hippomjrinx. 

 Genus HIPPONYX, Defrance, 1811). 



Sowerby , in the first volume of his Thesaurus, has monographed 

 this genus, consisting then of five species, as a bivalve mollusk 

 in connection with Crania and Thecidium, mistaking the occa- 

 sionally formed calcareous base for an attached valve. 



H. ANTIQUATUS, Linn. PI. 40, figs. 93-99. 



White, apex posterior, concentrically rudely, closely laminated, 

 more or less distinctly radiately striated ; epidermis pilose. 

 Length, *75 inch. 



Florida, West Indies, Senegal, Polynesia, 



California, Panama, Peru, Australia. 



The synonyms are H. mitrula, Gmel.; H. Panamensis, C. B. 

 Ad.; H.foliaceus, Quoy (fig. 98), and H. C7mra#=/orwm, Rochbr. 

 (fig. 99). 



H. SERRATUS, Carpenter. PL 40, fig. 100. 



Differs from H. antiquatus in the character of the base of the 

 shell (margin of aperture), which is broad and flat, made up of 

 very numerous close-set lamellae, deeply serrated into large, 

 scarcely rounded lobes ; the interstices are filled with epidermis, 

 in irregular ribband-like shreds. Length. 1 inch. 



Mazatlan. 



Living attached to each other or to other shells. //. foli- 

 aceus, Menke (not Quo}' and Gaimard\ is probably a synonym. 



H. SUBRUFUS, Lam. PI. 40, fig. 1. 



' / O 



Shell orange or orange-red, decussated by radiating and con- 

 centric close striye. Length, *5 inch. 



West Indict, Peru, Panama. 



H. cernuus, Gmel., is probably identical. 



H. tuberculatus, Carp., is similarly colored, with subcentml 

 apex, close radiating ribs and concentrically tuberculate, base 

 thick, lamellate. Length, *5 inch. 



Morch refers it here doubtfully. H. trigonus, Gmel., is said to 

 be flatter than subi-ufus, with stronger radiating sulci, and to 

 this^ Morch doubtfully refers H. barbatus, var. costdlatvx of Car- 

 penter; it is perhaps only a variety of subrufus. 



