GODWIN-AUSTEN : ANATOMY OF NEW: HELICARION (?). 297 
a well-marked furrow lying in the centre line, from which the main 
parallel side furrows are given off. The general colour is pale horny, 
with darkish grey near the tentacles and extremity of the foot. The 
sole of the foot is narrow, with a distinct central area. The peripodial 
margin is broad, with indistinct fringe lines, and two close parallel 
lines above it. Both the right and left shell-lobes are large, broad, 
elongate, and thin; on both can be seen a central vein, with branch 
veins leading towards the margin. The right dorsal lobe is rather 
small, the left is in two distinct parts; the posterior, although so 
extremely thin and transparent, was very well seen. It is evident 
that in life the shell-lobes spread over the entire upper surface of 
the shell. 
The generative organs (Fig. 1e) are simple. The penis is seen on 
the left dorsal side on removing the mantle-zone (Fig. 1a); it is 
bent on itself. The position of the retractor muscle cannot be made 
out, but it very probably has its attachment at this point; a muscle 
attachment is seen lower down. The spermatophore is indicated at 
the distal end by some regular oblique folds. The vas deferens is 
an extremely thin thread, becoming larger and more swollen close 
to the male organ, along the side of which it is attached by muscular 
tissue. The spermatheca is short, with a blunt knob, pointed where 
the retractor muscle is attached; the latter is large and flat, and 
nearly as long as the spermatheca. The free oviduct above is narrow, 
long, and coiled. 
The jaw (Fig. 1d) is concave on the cutting edge with a central 
projection. The radula (Fig. le) in the single specimen examined is 
evidently abnormal in all the central area; the centre tooth could not 
be seen (by analogy it would be of the usual tricuspid form); the 
admedian teeth are very irregular in size and form, the plates having 
developed, at their point of origin, two or three together ; the type of 
admedian teeth could, however, be discerned on one side, where five of 
the plates became regular and normal, and they present one single tooth 
with a small cusp on the outer side; the marginals that follow are 
curved and bicuspid, the imner point being longer than the outer. 
They are quite perfect in‘form. The formula would, I estimate, be 
35: 12:1: 12: 385; taking the total breadth of the radula, in 
its central area, and the number of admedian teeth that would fill 
the interval; it is also pretty clearly seen whether two or three teeth 
are grown together. There is only one other specimen left, which 
shows the form of the animal and its mantle-lobes so well that I have 
refrained cutting it up merely to extract another radula. 
The interesting points in this species are the great length of the 
foot and the great expanse of the shell-lobes, with the conspicuous 
central vein. The Doctors Sarasin, in their work ‘‘ Die Land-Mol- 
lusken von Celebes,” pl. xvii, fig. 149, show a somewhat similar veined 
structure in the large right shell-lobe of Helicarion /de. The radula 
is of a different type, with multiserrated marginals, and the foot of 
the animal is widely different in form from that of the present species, 
so I think it safe to say this New Britain form has little relationship 
with that species. 
