Bay of Bengal and the Arabian Sea. 9 
strongly striated, the keel is smooth, the apical whorls are 
differently sculptured, and the base of the shell is more 
strongly concentrically striated. The pale brown spots and 
dots, which characterize that species, are altogether absent in 
the present form. The localities of these species being in the 
same ocean and so close together, seems to suggest that they 
may be modifications of one and the same form. 
Dentalium mirificum. (Pl. IL. fig. 1.) 
Testa parva, versus apicem valde curvata et acuminata, quadrate 
tubiformis, latereincurvato latiore quam exteriore, longitudinaliter 
tenuiter striata, lineis incrementi tenuissimis sculpta, inter angulos 
subconcava. 
Longit. 19 millim., diam. max. 23. 
Hab. Station 172, off Trincomalee, in 200-350 fathoms. 
This little species is remarkable for the sharply curved 
end and the subquadrate form. The four angles are acute at 
the tip, but gradually become obtuse as the shell increases. 
The incurved side is the broadest of all, and up the middle of 
it, especially towards the apex, there is a raised striation more 
conspicuous than the rest. This is so prominent at the end 
that, when viewed with the opening towards the eye, five 
angles are visible. The two angles on the excurved side, 
which is the narrowest of all, become almost obsolete near the 
aperture. 
The form of the aperture, owing to the greater width and 
flatness of the incurved side, is very like the letter D. 
Siphodentalium quinquangulare, Forbes, is a much more 
slender species, and more circular in section near the aperture. 
I have placed this species temporarily in Dentalium, as 
the tips of the four specimens examined are all damaged. 
Possibly more perfect examples may exhibit slits, as in 
Siphodentalium. 
Venus juvenilis. (Pl. II. figs. 2, 2 a.) 
Testa minima, inequilateralis, postice subquadrata, antice angustior, 
rotundata, pallida, vel dilute fuscescens, liris radiantibus tenuis- 
simis, lamellisque concentricis numerosis supra liras subnodosis, 
minute cancellata ; umbones antemediani, incurvati, erosi; lunula 
cordiformis, sulco circumdata; pagina interna alba, margine 
undique minutissime denticulato ; cicatrices magne; sinus pallii 
haud profundus, triangularis. 
Longit. 9 millim., alt. 8, diam. 53. 
Hab. Station 162, Bay of Bengal, off Coromandel coast, 
in 142-400 fathoms. 
