154 Transactions.—Zoologij. 
Professor Huxley (Anat. of Invertebrated Animals), on the authority of 
M. Milne-Edwards, describes the spring and the piston-like body as re- 
sembling the sponge of a gun with a spiral screw turned on the handle. I 
have carefully endeavoured to confirm this observation so far as the species 
under notice is concerned, but have not been able to do so. There seems 
to be always a spirally coiled thread encased in a transparent tube or 
sheath. The nearest approach to an axis bearing a screw is when the coils 
are thrown close together, as often happens. I have added a sketch (fig. 7) 
of a close portion of a coil, drawn from the + in. objective with the camera 
lucida. 
Female.—The only female specimen I have been able to obtain is a very 
small one (about 2 inch. in length) and much mutilated. The organs I have 
been able to observe are the long, narrow, nidamental glands, lying on the 
median line just above the gills, the oval flat and apparently stalked acces- 
sory glands immediately below them, and the ovary. The ovary in this 
specimen is very small and is somewhat pyramidal in shape, the apex lying 
at the upper end of the body. I am not sure that I have correctly observed 
the oviduct, but what I take to be the oviduct opens on the left side, having 
passed under the branchial heart. 
(Nore.—The fact that this specimen is the only female among ten that I 
have examined, and that the males were all fully ready for congress, would 
seem to show that sexual selection may have considerable scope among 
the members of this species.) 
Alimentary System, (pl. vii. 
Mandibles (fig. 2).—Within the annular inner lip already noticed, are two 
vertical conchiolin jaws forming the beak, the posterior jaw overlapping the 
anterior one. The exposed parts are reddish-brown in colour, while the 
covered parts are transparent and colourless. Hach jaw consists of an 
uncus, ale and apophysis, the ale being backward and lateral expansions 
of the uncus. 
In the anterior or upper-jaw the uncus runs forward in a decurved line, 
terminating in a sharp point. The outer border of the ale forms a con- 
tinuous curve with this line, and runs backward to about half the length of 
the apophysis, from which it stands out prominently. The lower border of 
the ale is a concave curve; and the front border, from the margin of the 
uncus, presents a waved outline. The apophysis extends downwards, its 
greatest length being at its outer margin. It is fully twice the size of uncus 
and ale. Its inner border forms a convex curve, which extends round to 
the under-border, where it becomes concave. 
In the posterior or under-jaw the uncus is not so large as that of the 
upper-jaw, is more obtuse, and is proportionately stouter. The ale extend 
