182 ODONTOSYLLIS CTBNOSTOMA. 



2. Odontosyllis ctenostoma, Oldparede, 1868. Plate LXX, fig. 12— foot; Plate 



LXX1X, figs. 5 and 6 — spine and bristle. 



Specific Characters. — Head rounded, with short palpi in front, and ventrally pro- 

 jecting separately in the preparations. Eyes four, large, the anterior with lenses and 

 distinctly separated from each other, nearly forming a square. Median tentacle slightly 

 longer than the lateral. None of the appendages articulated. Body like that of 

 0. fiulgurans, and about an inch in length. The segments are banded transversely with 

 greyish granulations which also occur on the gibbosity, and the general colour is green, 

 like that of Bryopsis, amongst which it occurs (Marion and Bobretzky). Six teeth occur 

 in the proboscis anteriorly. The proventriculus commences at the eighth bristled 

 segment. The foot forms a short cone slightly bifid at the tip. Dorsally is the 

 moderately long cirrus, which is slightly tapered toward the tip. The setigerous region 

 has two pale spines with a beak and crown (spike) at the tip. The paler bristles issue 

 between the blunt papilla at the tip, are curved distally, dilated at the end of the shaft, 

 and the convex edge and tip are finely serrated. Terminal piece short, with a simple 

 boldly-curved hook at the tip. The front edge is concave and finely spinous. In 

 Claparede's figure of the compound bristle a tooth occurs on the anterior margin of the 

 terminal piece near its base, as in Odontosyllis fiulgurans. Langerhans, however, shows 

 none, and points out that the proboscis (his pharynx) is longer than in the latter species. 

 Ventral cirrus short and broadly lanceolate, the tip falling short of that of the setigerous 

 region. 



Synonyms. 



1868. Odontosyllis ctenostoma, Claparede. Aimel. Nap., p. 202, pi. xii, f. 4. 



viresceus, Marenzeller. Sitzb. k. Akad Wiss. Wien, Bd. lxix, p. 41, Taf. iv, f. 2. 



Marion and Bobretzky. Ann. Sc. Nat., 6 e ser., torn, ii, p. 42, pi. iv, f. 12. 



Langerhans. Zeitsch. f. w. Zool., Bd. xxxii, p. 555, Taf. xxxii ; f. 16. 



Cams. Fauna Medit., ii, p. 230. 



Allen. Jonrn. M. B. A., n.s., vol. vii, p. 219. 



Graeffe. Arbeit. Zool. Stat. Triest, xv, p. 323. 



Be St. Joseph. Ann. Sc. Nat., 9 e ser., t. iii, p. 185. 



Habitat. — Plymouth, between tide-marks, under stones, and amongst sea- weeds and 

 sponges (Allen). 



Naples. Marseilles (De St. Joseph, Marion and Bebretzky). Adriatic (Marenzeller). 

 Common at Cannes. 



Head, like that of 0. fidgurans, rounded in front, and with four distinct, brownish eyes 

 nearly in a square, the anterior pair having lenses. They are distinctly separated from 

 each other, yet Claparede states that they are almost coalescent. The palpi form short 

 projections — best seen from the ventral surface. Tentacles and tentacular cirri similar to 

 those of the species mentioned. 



Body like that of 0. fiulgurans, and ranging from 18 mm. to 25 mm. or even to 1 cm. 



1874. 



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1875. 



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1879. 



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1885. 



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1904. 



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1905. 



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1906. 



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