492 MACROCHATA CLAVICORNIS. 
MaAcROCHATA CLAVICORNIS, Sars, 1835. Plate CXX XVI, fig. 14—dorsal bristle, and 14a and 
14b—compound hook-like bristles; Plate CXX XVII, fig. 7—enlarged view of body ; 
Plate CXXXVIII, fig. 12—-processes of the surface of the body. 
Specific Characters.—Head distinctly defined, with a median process to the blunt snout, 
and four dark eyes arranged nearly transversely, the larger bemg external. Two clavate 
palpi from the peristomial segment. Four pairs of somewhat clavate cirri from the next 
four segments. Body from 0°75 to 1 cm., somewhat spindle-shaped in spirit and densely 
covered with papille. Tufts of long translucent bristles with minute spines occur dorsally ; 
ventrally are peculiar flattened, large transparent and articulated hooks, with bifid tips. 
SYNONYMS. 
1835. Nazis clavicornis, Sars. Beskriv. og. Jagt., p. 64, pl. 1x, fig. 24 a—d. 
1851. Macrocheta clavicornis, Grube. Fam. Annel., p. 64. 
1880. 5 Langerhans. Zeitschr. f. wiss. Zool., Bd. xxxiv, p. 95, Taf. i, fig. 7. 
1883, . Levinsen. Vid. Meddel. naturh. Forh. Copenhagen, 1883, p, 298. 
1894. a Ss Bidenkap. Forhandl. Vidensk. Selsk. Christ., p. 94. 
1898. . 4 Caullery and Mesnil. Annel. Univ. Lyon, Fasc. xxxix, p. 180. 
1914. ij a Southern. Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 120. 
- ee ‘x Fauvel. Annél. Polych. Monaco, p. 21. 
1922. 55 - McIntosh. Ann. Nat. Hist., ser. 9, vol. ix, p. 24. 
Habitat.—Blacksod Bay in corallines; in Laminarian roots on the shores and dredged 
in a few fathoms in the former and in Clew Bay; Ballynakill Harbour (Southern). 
Distribution.—Norway (Sars) ; Madeira (Langerhans). 
In general aspect (Plate CX X XVIL, fig. 14) at first sight this form resembles a Chloreemid, 
and it has a densely papillose skin, and long, slightly spmose bristles. The papille agree 
im minute structure with those of the Chloreemids, and mud and sand occur in the interstices. 
Its phosphorescence, however, is a feature at variance with that group, and more in conson- 
ance with the Syllids. The pigmented anterior region ends bluntly, with a median process 
(somewhat like the central apparatus of Stylarioides arenosa), but the other parts diverge. 
The four eyes, arranged nearly in a square, are very distinct. 
The simple, spinous dorsal bristles (Plate CX X XVI, fig. 14) differ from those seen in 
various groups, and notably from those present in certaim Syllids, and are slender elongated 
forms tapering to a hair-like point. The anterior and posterior hooks, or compound hook- 
like bristles, do not differ much from each other, both having the tip strongly curved and 
pointed (Plate CXXXVI, figs. 14a and 146), with a wing-like process also with an acute 
tip. The papille on the body (Plate CX XXVIII, fig. 12) differ from those usually seen in 
the Chloreemids, and lean to a type sue generis, for such appendages are unknown in the 
Syllids proper. 
The example, kindly sent by Mr. Southern, is mature, since the posterior region had 
many large ova. The alimentary canal harboured Opaline with two vacuoles. 
Marion and Bobretzky! (1875) describe Heterocirrus frontifilis, Grube, from Marseilles, 
which, in many respects, agrees with Macrocheta. 
1 “Ann. Sc. nat.,’ 6° sér., t. ii, p. 64, pl. viii, fig. 18, and pl. ix, fig. 18. 
