88 
Length, 27:5 mm. ; greatest breadth, 16 mm. ; length of aper- 
ture and canal, 17°5 mm.; greatest width, 7 mm. 
Habitat.—Backstairs Passage, 8.A. Dredged alive in 22 
fathoms ; one example in my collection. 
From 7. Flindersi it differs by being much thinner, narrower, 
spire more acute, whorls less angulated, outer lip thin, not denti- 
culated, columella not so excavated, umbilicus smaller, canal 
more open; surface much less sculptured. 7. Mlindersi is a 
littoral shell. 7’. Jevis was dredged in deep water. It is possibly 
only an extreme variety resulting from its very different station. 
Triton mimeticus,.7ate (StpHo?). PI. 2, figs. 4, 4a. 
In the Proc. Roy. Soc. of 8.A. for June, 1893, p. 189, Prof. 
Tate described a shell which he referred provisionally to Sipho, 
recognising it as probably immature, and as needing further 
material to determine its generic location. This material has 
been furnished by two more specimens dredged by me in Investi- 
gator’s Straits, one of which is slightly less immature than the 
type, and the other has formed two varices, and so established 
its position asa Triton. It is an interesting form in two re- 
spects, viz., the comparative length of its canal, and the delay in 
forming its first varix until about four and a-half whorls have 
been completed. I have given below a full description of the 
shell. 
Shell ovately-fusiform, imperforate, rather thin. Whorls 
nearly six. Spire moderately elevated, one-third the length of 
the shell, as 7 to 21; whorls 5, including nucleus. Nucleus one 
turn and a-half, slightly oblique, apex nearly flat and forming a 
sharp angle with the short steep side in the first turn; second 
turn subconvex. Spire-whorls, the first slightly and medially 
angulated, the second with a marked shouider at first median, 
but gradually approaching the suture, which it reaches about the 
middle of the third spire-whorl and runs in apposition with it 
for the third of a revolution, when the first varix is formed, and 
the suture sinks again to reascend just before the next varix is 
produced. Suture distinct. Whorls subconcave behind the 
shoulder, with spiral lire, increasing in number with the size of 
the shell, about six in the penultimate and two interstitial 
threadlets ; lire rounded, narrow, about half the width of the 
interspaces; longitudinal growth-lines at unequal intervals, 
making the spiral lire somewhat moniliform ; obsolete longi- 
tudinal coste, most marked at the angle, where they produce a 
row of tubercles, 15 on the penultimate whorl. Body-whorl 
large, angulation well-marked, with less pronounced carina in 
front, so as to divide the whorl into three equal parts; concave 
behind the angulation, flat and sloping to carina, excavated 
