184 PARATHBLBPUS COLLARIS. 



arising as a group on each side of the frilled lamella, Dorsal eyes. Body similar to that 

 of Thelepus, but with rows of glands encircling the second and third segments. Branchiae 

 on the second and third segments, simple, rather stiff, lateral in position. Bristle-tufts 

 15, commencing on the third segment; simple, capillary, bristles with narrow wings and in 

 two groups. The avicular hooks commence on the eleventh segment. 



1. Parathelbpus collaris, Southern, 1914. Plate CXXV a, figs. 6—6 b— bristles 



and hooks. 



Specific Characters.— Cephalic region as in the genus, the first segment having two 

 lateral groups of dark brown eyes, and extending ventrally as a shield-shaped area with a 

 smooth margin. Body about an inch or more in length, somewhat rounded dorsally and 

 slightly flattened ventrally, the segments increasing in antero-posterior diameter from 

 before backward. As it tapers anteriorly and posteriorly it is somewhat spindle-shaped. 

 Branchiae, as in the genus, 4 rather longer pairs on the second segment, two pairs on the 

 third; slightly grooved. Bristles pale, the longer with more tapered, slender tips and 

 slightly convex posteriorly, the shorter with less elongate tips. They commence on the 

 third segment and continue for fifteen segments. Third and fourth segments have rows 

 of glands in line with the bristles. Hooks minute, with two teeth above the main fang, a 

 crown convex posteriorly, the outline again dipping inward above the posterior process of 

 the base, which is rather long and has a curved inferior border. The anterior 

 margin from the main fang to the prow has a spicular process directed outward and 

 downward. The hooks bear a resemblance to those of Streblosoma bairdi, though 

 much smaller. They begin on the eleventh segment (ninth setigerous), and are in a 

 single row. 



Synonyms. 



1914. Thelepides collaris, Southern, Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 125, pi. xiii/fig. 30. 



1915. Parathelepus (Thelepides) collaris, idem. In lit. 



„ „ collaris, Caullery. Bull. Soc. Zool. France, t. xl, Nos. 1 — 3, p. 47. 



1917. „ „ Hessle. Zool. Bidr. Uppsala, p. 219. 



Habitat. — Dredged in 15 fathoms in Clew Bay on stony ground (Southern). 



The cephalic region has a frilled lamella surrounding the mouth, and this is partly 

 cleft dorsally and completely ventrally, where a small independent process occurs, as in 

 Proclea. On the dorsum of the first segment are on each side two conspicuous groups 

 of eyes which remain in the spirit-preparation, whilst ventrally is a shield-shaped area 

 with a smooth margin. The tentacles arise in a group on each side of the frilled oral 

 lamella. 



The body is somewhat spindle-shaped, being slightly enlarged in the anterior region, 

 diminished toward the head, and more distinctly tapered posteriorly. It is about an inch 

 in length. Anteriorly the segments are four times as broad as long, then they gradually 

 increase till in the posterior region they are much longer than broad. On the third and 

 fourth segments is a conspicuous line of glands with elongated cells. The sole fragment 

 had twenty-nine segments, twenty-seven of which were armed. 



