FILOGRANA IMPLEXA. 343 
colour is translucent orange, with the intestine dusky brown. It tints the tube, so that 
it has a faint reddish hue when the animal is within. ‘The branchie are pale. 
The first region of the body has seven or eight pairs of bristle-tufts, which, with the 
peristomial segment, make a total of eight or nine. The second region has from thirty- 
five to forty segments. The body is somewhat flattened both dorsally and ventrally, with 
a median groove in the posterior region on both surfaces, and terminates posteriorly in an 
anus, which has a prominent papilla at each side, and this, according to De St. Joseph, may 
assist in the formation of the tube. The anterior region has the alar membrane stretching 
from the collar along each side to the posterior edge of the last segment of the anterior 
region, where it bends ventrally and fuses with that of the opposite side as in Protula, leaving 
a free flap posteriorly. It forms a more uniform margin than in Protula, and 1s in the 
preparations generally directed obliquely upward and outward, the bristle-tufts being 
beneath, and so closely applied as to appear to be oblique rays supporting it. 
The first or collar bristle-tuft is directed outward and forward, and the bristles have 
translucent straight shafts, and a knife-shaped, tapered tip, with a broader and coarsely 
serrated base and a differentiation or “ bite” at the edge of the blade, the serrations on the 
distal region bemg so minute as to be almost indistinguishable (Plate CXNX XVII, fig. 20). 
From this simple or less boldly developed form the increase in the size of the basal and distal 
serrations may be followed, to culminate in the highly developed condition in Salmacina 
imcrustans and L. edificatria of other authors. The six pairs of bristles which follow slope 
upward and backward, have similar translucent straight shafts, but the tapered tips, which 
are bent at a shght angle (geniculate), are more slender. Moreover, the presence of sickle- 
shaped bristles (Plate CX X XVII, fig. 20a), about two in each tuft, is a noteworthy feature. 
The second region of the body is devoid of bristles for a short distance, whilst the posterior 
part has them in pairs, the tips being long and finely tapered, with distinct wings (Plate 
CXXXVII, fig. 200). 
The minute, translucent, anterior hooks (fig. 20c) have a nearly straight anterior edge 
serrated throughout and ending below in a main fang, the outline being continued with a 
curve below the hook and terminating at the basal edge. The crown is mimute and the 
posterior outline slopes to the base, which appears to have a straight edge. The rounded 
projection below the main fang shown by De St. Joseph in Filograna implexa difiers from 
that of the present examples. These hooks are situated slightly behind and to the ventral 
side of the bristles, and form considerable rows. The posterior hooks are smaller, but agree 
in structure with the anterior. They are placed on the dorsal side of the bristle-tufts, and 
are few in number in each row. Like those of its alles, these minute, thin hooks cling 
together so closely that it is difficult to get a lateral view of a single hook. 
Reproduction.—The eggs are red, and the embryos resemble those described for Salmacina 
Dysterr. The spermaries seem to develop a little later than the ovaries, none, indeed, 
appearing in the bud, but by-and-by they fill the non-bristled region in front of the ovigerous 
segments, and bulge laterally, the region being thus characterised by its pallor. 
Karly trochophores of a deep red colour occurred in the glass vessels of sea-water on 
the 9th June, the prototroch being visible on each side. They simply rotate or swim in 
small circles, but the larve with commencing segmentation of the body dart through the 
water with great vigour, and often in a straight line, whilst others make larger circles near 
