SPILEBODORID^. 45 



Some of the eyes have lenses. A retractile and ciliated nuchal organ occurs on each 

 side as in Gapitella and Polyophthalmus. After a general description of the annelid, he 

 concludes that it resembles the Spionidee in its head, the Capitellidae and OpheliidaB in 

 the vibratile nuchal organs, and Polyclora and Disoma in its great anterior bristles. 

 But it truly pertains to the ScalibregmidaB, for the posterior region is slender and 

 terminates in delicate cirri, the proboscis is round and short, the foot has two setigerous 

 lobes with simple and bifid bristles, and the surface of the body is tesselated. It differs 

 in the absence of branchiae. 



De St. Joseph describes the segmental organs as present in all the segments, except 

 the first seven and the last twelve. The outer part consists of a brownish canal ciliated 

 internally, curved on itself, and which debouches ventrally on a papilla at the base of the 

 lobe of the foot. Internally it is translucent, forms an angle with the coloured part, and 

 ends in a ciliated funnel which he describes as fixed to the wall of the body, though he 

 probably refers to the homologue of a dissepiment. He considered the organs excretory, 

 and that they likewise act the part of gonaducts. 



The curious form, Nevaya Whiteavesi, Mcintosh, 1 dredged in the Gulf of St. Lawrence 

 by Dr. Whiteaves, bears powerful hooks on the second foot, which probably is connected 

 with the habits of the annelid, as in Sclerocheihis. 



Family XVII. — Sph^liodobilve, Malmgren. 



Cephalic region conical, with short papillae and four eyes. Proboscis smooth. Body 

 somewhat like that of a Nematelminth, but with numerous segments, each uniramous foot 

 having a conspicuous globular papilla. Anal segment with a papilla on each side. 



In transverse section the body-wall (Fig. 105) has externally a firm transparent cuticle 

 which is raised into numerous papillae (p) with a central process of hypoderm which does 

 not seem in the preparations to reach the surface, though it may have done so in life. 

 Beneath is a very thin layer of hypoderm, the largest mass being in the mid-ventral line 

 below, i. e. external to the nerve-trunks, and it separates the ventral longitudinal muscles, 

 which form a thin belt on each side up to the origin of the oblique muscles. The dorsal 

 longitudinal muscles are also rather thin. The nerve-cords are separate, appearing in 

 front as two flattened cords, and in the middle as two rounded masses in section above 

 the hypodermic area and separated from it by a stratum of neuroglia. The trunks fuse 

 at the ganglia. The slender oblique muscles touch their exterior and are inserted into 

 the basement-tissue beneath them. 



In sections of the anterior end the proboscis, when drawn in, has a dense sheath of 

 longitudinal fibres, then a thick circular layer, within which are the basement-tissue and 

 the densely papillose lining. In the middle of the body the digestive canal forms 

 in section an ovoid granular structure, and posteriorly it is voluminously folded. 

 Whilst in some the coelom is filled with large granular cells (gs.), in others large 

 rounded ova with a tough and minutely papillose capsule occurred in the anterior 

 sections and perhaps represent ripe eggs, the capsule resembling that in certain Spionids. 



1 ' Ann. Nat. Hist./ ser. 8, vol. vii, p. 149, etc. 



