NASSIDA, 159 
drained at low tide. It is found abundantly at the confluence 
of fresh and salt water, where the taste is merely brackish. No 
shell of equal size is so abundant on the whole Atlantic shore. 
The younger shells are most likely to be collected, because the 
old ones become very much eroded and defaced, and a greenish 
mould-like plant vegetates abundantly upon them. Very few, 
therefore, of the shells usually collected, have the lines on the 
interior of the outer lip. The ova-capsules are laid during April 
and May, are of transparent corneous texture, singly attached to 
the inside surface of a valve of Mactra, or the inner face of the 
nidus of Natica; they are deposited in vast numbers, completely 
covering the object to which they are attached and crowded 
together promiscuously. 
VENASSA, von Martens. Base with a callous spiral deposit 
encircling the indented umbilicus. N. pulvinaris, von Mart. 
Timor. 
PTYCHOSALPINX, Gill. Shell ovate, buecinoid, whorls regularly 
rounded and ventricose ; spire moderate (about as long as the 
aperture), furnished with equal revolving linear ridges, siphonal 
canal very short, very obliquely twisted and concurrent with the 
siphonal fasciole ; aperture rhombo-ovate, oblong ; labrum entire, 
not sinuous, smooth within; columella inversely sigmoidal, con- 
cave near the middle, with a very thin callous deposit and with 
a revolving linear plait in front. Dr. Gill refers this group to 
the family Buccinide, but I agree with the late Mr. Conrad that 
his description indicates (as do the types cited) Nass. N. 
scalaspira, Conrad (lii, 95). Miocene; Virginia. 
PARANASSA, Conrad. Differs from Ptychosalpinx in the sub- 
margin of the labrum being slightly thickened within and striate ; 
siphonal canal shorter. Eocene, Miocene; America and Europe. 
N. granifera, Conr. (lii, 96). Virginia. As one of the two spec- 
imens of the type of Paranassa is striate within the aperture, 
while the other is smooth, probably the distinction from Ptycho- 
salpinx will not hold good. 
TRITIARIA, Conrad. Elongated, subturreted, labrum not thick- 
ened within. This does not seem to differ generically from the 
true Nassas; it has very little resemblance to Ptychosalpinx. 
N. peralta, Conrad (lii, 97). Miocene; Virginia. 
NeErITULA, Plancus. 
Syn.—Cyclops, Montf. Cyclonassa, Swains. Nana, Schum. 
Cyclocyrtea, Agass. 
Distr.—3 sp. Mediterranean, Black Sea. N. neritea, Linn. 
(lii, 98, 99°. 
Shell ovate, depressed, axis distorted ; spire flattened, oblique, 
whorls smooth ; aperture depressed ; columella smooth ; inner lip 
