436 PELAGOBIA LONGICIRRATA. 
The post-larval examples procured in the Irish Seat present two stages—different from 
those figured by Reibisch, but agreeing in general structure. The younger has three bristled 
segments (Plate CN XXIV, fig. 4), the large head (for at its posterior border it is equal to the 
diameter of the body), is broadly shield-shaped, the narrower border being anterior. Two 
eyes—antero-posteriorly elongated—occur toward the posterior border and are widely sepa- 
rated. A tentacle projects on each side of the anterior margin. The second pair arise behind 
each eye, are subulate in shape, and slant forward. A pale area in the centre of the snout 
indicates the mouth, which is at the anterior extremity; a small ovoid area occurs in 
the lateral region, and probably indicates the nuchal organ, which is conspicuous in Greef’s 
form. The head thus differs from Greef’s in the antero-posteriorly elongated eyes and in 
the brevity of the tentacles, but it has to be remembered that his form is much more advanced. 
The body is nearly cylindrical, though the two terminal segments are considerably 
narrower, and has three bristled segments, the first feet being the shortest, a brief interval 
separating them from the head. Hach forms a simple blunt cone standing at right angles 
to the body and furnished with a series of delicate translucent bristles with articulated 
terminal pieces like those of Phyllodocids. The second feet are considerably larger, also 
stand nearly at right angles to the body, and their bristles are longer and stronger. The 
third pair slope distinctly backward. Hach foot, except the last, has a small subulate dorsal 
enrus which projects only a little beyond the tip of the setigerous lobe, and is in contrast 
with the two long cirri of Greef’s type. Behind the third foot is a narrow segment with 
a sheht lateral projection from which a single bristle projects. Then follows the still nar- 
rower anal segment which has two subulate anal cir. If Reibisch’s figures are to be trusted, 
this species would appear to differ, since he shows only two conical processes terminating 
the body, but perhaps the cirri had been lost. In the origimal description of Greef the anal 
cirri are almost bulbous at the base, with a terminal slender, subulate process. 
The proboscis occupies the first bristled segment, is nearly circular in outline, with a 
median fissure from which transverse striz pass. A narrow process of the gut joins this 
to an enlargement between the second and third feet, after which the intestine diminishes 
to the terminal vent. 
The second example (Plate CX XXIV, fig. 4a) has advanced a little, since the fourth 
foot now projects with its tuft of bristles, the anal segment remaining as before. The anal 
cirri spring close together on the ventral surface, and extend backward as short subulate 
processes, their total length being about the transverse diameter of the anal segment. They 
present no bulbous base as in Greef’s species, and differ from the stumpy, conical condition 
shown throughout all the stages of Reibisch’s examples. 
Greef’s” specimens were procured in the Bay of Arrecife, Canary Islands, from January 
to May. The body had fifteen segments and was 3 mm. in length. The head and first 
seoment had a reddish tint; the rounded, reddish-brown eyes, situated a little behind the 
bases of the dorsal tentacles, had lenses ; whilst the mouth opened at the tip of the snout. 
On each side of the posterior part of the head is a ciliated, lobate nuchal organ. The first 
segment bears a pair of rather long cirri and a setigerous process ; the second has shorter 
cirri, but the third, again, has somewhat longer cirri, and they get broader posteriorly. The 
! For these examples I am indebted to Mr. Chadwick, of the Port Erin Marine Laboratory. 
2 «Zeitschr. f. wiss. Zool., Bd. xxxu, p. 247, Taf. xiv, figs. 23, 24 and 25. 
