144 
then flatly expanded with numerous (perhaps eight) fine setze 
on either side, beyond these the seta bifurcates ; one part con- 
tinues nearly in the same axis, and is the larger and longer; 
the other stands out at an acute angle and generally divides 
into two. Resting on the operculum, in the throat of the 
shell, may be three or four embryos, like minute nautilus. 
Cylindrical portion about 6 millimetres in diameter and 4 
or 5 high ; aperture 3 or 4 in diameter. 
Hab.—Backstairs Passage, from 16 to 23 fathoms, many 
alive. 
I compared this species with a solitary small specimen in 
the British Museum, of unknown habitat, said to be a type 
of Vermetus senticosus, Mórch, and regarded it as identical. 
But a comparison of the nucleus of our shell with the descrip- 
tion and figure of the type of Mórch's shell, given in P.Z.S., 
18601 P TOO, Dl RE, figs. 2 and 14, disproves this. The few 
large tubercles of his figure are quite different from the nume- 
rous minute granules of ours, aad the 25 valid тапта Ше at 
the periphery are wanting in ours. Then the form of the 
opercular setz is quite dissimilar. Ours has not the expand- 
ed, sub-basal lamina he depicts, nor has his the bifurcation 
which ours always shows. His description indicates his pos- 
session of several shells, and not one only. Possibly the Bri- 
tish Museum specimen may not have been the actual indi- 
vidual taken as the type, though resembling it externally, 
but may be the species now described. 
Nacella crebrestriata, sp. mov. Pl. xxvi , figs. 20, 21. 
Shell oblong-ovate, laterally compressed, depressed conic. 
Apex subcentral, somewhat anterior ; rounded, simple. About 
sixty radial riblets, rounded, about as wide as the inter- 
Spaces; fine microscopic accremental stris. Translucent, 
with an opaque, white apex, and a white flame in the centre 
of the upper half of the steep anterior slope ; on the posterior 
slope, іп its upper half, is a series of about seven opaque, 
white, concentric markings, consecutively increasing in trans- 
verse extent. The muscie scar is open towards the shorter 
end of the shell. Length, 3:8 millimetres: breadth, 2:1; 
height, 1:8; apex, 121 and 2'7 from the margin. 
Hab.— "South Australia," from Professor Tate's collection ; 
no more exact locality given. He had labelled it Scutellina ; 
but that genus has the apex directed away from the opening 
of the muscle scar. Its size and shape recall our Nacella 
parva, Angas, from which it differs in being more solid and 
in its radial striation. i 
