462 PROCERASTEA. 
Habitat.—Blacksod and Clew Bays, Ballynakill Harbour (Southern). Common in 
dredgings from Duke Rock and the rocky ground south of the Breakwater, Plymouth. It 
also occurs in tubes attached to the fronds and roots of Laminaria in the same region (Allen). 
Distribution.—De St. Joseph found it amongst the roots of Laminaria, and dredged 
amongst Sertularia operculata. 
The body of this species has a longitudinal streak of orange on each side of the dorsum 
in the nurse-stock, and the appendages of the head (Plate CXXXV, fig. 18) have, with the 
first three segments, orange tips. 
De St. Joseph observes that he occasionally met with an Autolytus which he could not 
distinguish from this species except by the absence of the two reddish-orange bands on 
the anterior segments. It also bore stolons, and he considered it a variety of this species. 
Allen found the breeding season from March to June at Plymouth. 
AUTOLYTUS LUGENS, De St. Joseph, 1886. Plate CXXXVII, fig. 6—head and anterior 
region. 
Specific Characters—Head comparatively small, surmounted by the massive median 
tentacle. Four eyes in the usual position. The lateral tentacles are small in comparison. 
Body typical, but small. The proboscis has only six denticulations, but is large, with a 
single volution. Proventriculus has twenty-six to thirty rows of grey points, and occupies 
segments 8—11. Reproduction by stolons. 
SYNONYMS. 
1886. Autolytus lugens, De St. Joseph. Ann. Se. nat., 7° sér., t. 1, p. 234, pl. xu, fig. 116. 
1915. i » Allen. Journ. M. B. A. ns. vol. x; p: 606: 
1921. i » McIntosh. Ann. Nat. Hist., ser. 9, vol. vin, p. 309. 
Habitat.—Several examples were dredged on Queen’s Ground and Millbay Pit, Plymouth 
(Allen). 
It was discovered at Dinard by De St. Joseph. 
The small head (Plate CX X XVII, fig. 6) is surmounted by a massive median tentacle. 
De St. Joseph met with specimens having male buds. Allen, again, observed stolons at 
Plymouth early in January and February, and a well developed one in July. 
This 1s one of the Sylhids which requires re-investigation, especially in connection with 
known forms. 
Genus PROCERASTEA, Langerhans, 1880. 
Proboscis formed of a single cylinder, longer than in P. nematodes, Langerhans. ‘Trepan 
armed with twenty to twenty-two teeth. Forty to forty-two segments before the period 
of reproduction, fifty-four to fifty-six on the appearance of the head of the stolon. Dorsal 
cirri developed only on the first setigerous segment. Feet with compound bristles—(1) with 
tips short, (2) with tip winged, and (3) simple bifid bristles in a group. Reproduction 
by stolons, with largely developed cirri. Colour uniform brown. Lives in the interior of 
Tunicates and in sponges, with Hydroids and Bryozoa. 
