1JJ4 THE VOYAGE OF H.M.S. CHALLENGER. 



I caimot discover any sufficient reasons for separating Ojtherea Ulacina and Cytherea 

 ijrata. The difl'erences of form, the thickness of the concentric costse, and the slight 

 variations in the depth and height of the pallial sinus are so changeable that one scarcely 

 finds any two specimens alike. Two that correspond as regards the strength of the ribs 

 may be unlike in respect of the form of the sinus in the pallial impression, and, on the 

 other hand, I find other examples agreeing in the latter respect but differing in the 

 former. Cytherea costata, Chemnitz, is also very closely related, and indeed insensibly 

 passes into this species through the variety fig. lih of the Conchologia Iconica. This is 

 regarded by Eomer as a form of Chemnitz's species. In my judgment, however, it comes 

 intermediate, agreeing in the general tone of its colouring with Cytherea grata, l)ut 

 being rather more strongly ribbed than the typical form of that species. The amount of 

 violet-red markings around the lunule and on each side of the dorsal area is also subject 

 to much variation. In Cytherea Ulacina there is either none at all or but very little, 

 whilst in the type of Cytherea grata there is considerable ; but in the series of specimens 

 before me I find some which have rather less. The lunule also varies in form and colour, 

 in some instances being much broader than in others, although the shells may eoi-ncide 

 in other respects. 



Cytherea [Callista) multistriata, Sowerby (PL I. figs. b-be). 



Cytherea muUitd7-iata,Sowei:hy,Thea. Conch., vol. ii. p. 628, pi. cxxxvi. fig. 177 (too highly 



coloured). 

 Dioiie multistriata, Deshayes, Cat. Biv. Brit. Mus., p. 64. (var. /J. exclusa). 

 Callista multistriata, Hutton, Man. N. Zeal. Moll., pp. 149 and 203. 

 (nee Cytherea multisfriatn, Etimer, Monogr. Venus, sub-gen. Cytherea, p. 72, pL xsi. tig. 1 ; 



nee Dione multistriata, Eeeve, Conch. Icon., fig. 60 = Cytherea diemenensis, Hanley). 



Habitat. — Station 1G7a, Queen Charlotte Sound, Cook Strait, New Zealand, at a deirtli 

 of 10 fathoms, mud ; Wellington (Hutton). 



No characteristic figure of this species has yet been published. That in the Thes. 

 Con. is much too highly coloured, and represents a specimen rather unusually high at 

 the umljones, with the dorsal margin more oblique on both sides than in the majority of 

 specimens. 



The form is oval, rather acuminate posteriorly. It is moderately convex, a little 

 glossy, finely concentrically striated, the intervening ridges resembling thread-like lirse. 

 It is very inequilateral, half as long again as high, of a buff colour, variegated with 

 interrupted rays and irregular wa\^ lines of a pinkish-brown tint, and frequently exhil)its 

 at intervals two or three bluish concentric zones. The interior is white, with a large 

 purple patch occupying the central and upper j)ortions of the valves. The lanceolate 

 lunule is generally light purple, and marked off by an impressed line. 



