/ 



138 THK VOYAGE OF H.M.S. CHALLENGER. 



Ct/therea {Can/atifi) hchrcm, Lamarck. 



Cijtherea hehneii, Limarck, Anim. sans vert., vol. v. p. .508, ex\. 2, vtjl. vi. p. 30.^. 

 Ctjthcrea hehrwa, Delesseit, Eecueil de Coq., pi. viii. fig. 6. 

 Cytherea hebroici, Hanley, Cat. Biv., p. 99, suppl. pi. xiii. fiy. 21. 

 Dionehehnea, Deshaj'es, Cat. Conchif. Brit. Mus., p. 67. 

 Cuxe hehntu, Keeve, Conch. Icon., fig. 34. 



Venus {Cytherea, sect. Caryatis) hehrcea, Eonier, Monog. Venus, p. 116. 

 ? Venus {Cytherea, sect. Caryatis) soligena, Ebmer, loc. cit., p. 118, pi. xxxii. fig. 1. 

 Cytherea sophiw, Angas, Proc. Zool. See. Lend., 1877, p. 176, pi. xxvi. fig. 23. 



Habitat. — Station 212, Malanipa, Philippine Islands, 10 to 20 fathoms, sand; 

 Cape Solander, Botany Bay, New South Wales, after a gale (Angas). 



This species appears to var}^ rather as regards shape. The typical form, judging 

 from Delessert's figure, is rather trigonal, acuminately produced at the hinder extremity. 

 Certain specimens in the British Museum are much broader at this pai't, yet are 

 evidently the same species. The single valve from the Philippines is remarkably short 

 and high, being less elongate even than the shell figured by Reeve. The young 

 example described by Angas under the name Cytherea sojihia? is rather more oblong than 

 usual, but in other respects agrees precisely with normal specimens of the species. The 

 small brown stain within the valves at the apex of the umbones is apparently present 

 in the majority of specimens, and forms a good distinguishing feature. When present, 

 it is also visible on the exterior, having the appearance of a livid or purplish stain (in 

 some instances darker than in others), chiefly upon the anterior side of the beaks. The 

 surface is rather glossy, concentrically finely striated, and exhibits at intervals shallow 

 grooves which probably indicate periods of growth. The lunule is large, ovate-cordate, 

 slightly excavated and very feebly elevated along the centre. It is circumscribed by an 

 incised line, and generally painted with wavy brown markings which do not appear ever 

 to cross the incised boundary. The dorsal area is not clearly defined, but merely 

 sunken along the middle, the surface of the valves gradually rounding over to the 

 margin. The umbones are rather prominent, well incurved, and situated at a point 

 Avhich does not mark ofi" one-third of the entire length of the shell from the anterior 

 end. The two cardinal teeth in the right valve, immediately beneath the beak, are 

 very small and very close together. The corresponding ones in the left valve are very 

 unec[ual in thickness and united above, the anterior being very slender and lamellar, 

 whilst the posterior is triangular and stout. The lateral tooth in this valve is 

 compressed, erect, and stands about a third of the way down the lunule. The anterior 

 muscular scar is nearly oval, the posterior much broader and rounded. The pallia! line 

 in the largest specimens has a ragged upper edge, and the sinus is largish, bluntly 

 triangular, the apex being sharply rounded, but does not reach quite to the centre of 

 the valves. The colour of this species is white, ornamented witli blotches of an 



