260 BISPIRA VOLUTACORNIS. 
In the posterior region the bristles form a cylindrical pencil, a slight swelling occurring 
distally where the wings project. Their tips are more finely tapered than in the first region, 
and there is a slight curvature at the commencement of the wmgs. The pencil springs from 
a distinct setigerous papilla. The bristles of the flattened caudal region again, while retaining 
as a group the form of a pencil, have the tips of the majority greatly elongated (Plate CX XVIII, 
fig. 5b), so that this region of the body is specially hirsute. No wings are visible in these 
much elongated forms, but in the shorter forms these are well marked and have serrated 
edges. The anterior hooks, which commence on the second bristled segment (Plate CX XVIII, 
fig. 5d), are situated on long, low flaps, eight in number, which stretch from the setigerous 
process almost to the ventral scute in each segment. They are in a single row, and are 
characterised by their somewhat long necks—a condition which may have misled Claparéde 
to give them a long manubrium, from which the main fang arises at less than a right angle, 
and has eight or nine small teeth above it in lateral view. The prow is rounded and prominent, 
but the base is short, for it abruptly tapers to a blunt point posteriorly. A series of bold 
strie occupy the central region from the crown to the base, into which they curve. Hach 
hook is accompanied by a short bristle with a thick shaft, a slight narrowing of the neck, 
then an enlargement of the base of the flattened, tapered tip, which is bent backward at 
an angle, and, according to position, is either symmetrical or asymmetrical. De St. Joseph 
found no less than 108—140 hooks in a single row in the anterior region. The posterior 
hooks do not differ except in the length of neck, smaller size, and in the presence of short 
striz on the neck at the base of the great fang. These may indicate a stage in the develop- 
ment of hook-like points on the region. De St. Joseph states these have smaller and shorter 
bases, and he gives the numbers in several examples. 
Reproduction.—A fine example procured in July in a chink of the rocks at St. Peter 
port is a nearly ripe male. 
A young example occurred in the fissure of the rock a few inches from the adult. When 
alive it appeared to be about half an inch in length. The anterior region has seven setigerous 
and six uucinigerous processes, whilst the posterior consists of about thirty-nine segments, 
the tip of the tail apparently being incomplete. Nine scutes are in front of those split 
by the mid-ventral line, instead of eleven in the adult, showing that whilst the two behind 
the anterior region are constant, the rest increase with age. The cephalic lamellz and folds 
are similar. The branchial filaments are respectively eleven and twelve, and they have 
the beautiful white tints of the adult, and the same basal web. The ocular pigment-spots 
in the preparation, however, are few and minute, some in all probability having been bleached 
by the spirit. The structure of the anterior and posterior bristles and hooks at this stage 
corresponds with that of the adult. 
In another young example found under a stone at St. Peter Port, Guernsey, and which 
was about three-quarters of an inch in length, the reflected lamellee of the collar were of a 
rich reddish-brown colour. The anterior region consists of ten bristled segments and nine 
long scutes, and the region which follows appears to have more than thirty segments. The 
body is comparatively short, grooved on the dorsum for a short distance behind the fissure 
of the collar, and rounded behind the anterior groove. The ventral surface is slightly flattened, 
and marked by the median furrow from the tenth scute backward. 
The tube of an adult measures fully nine inches in length, and is a little less than half an 
