1905.] NATURAL SCIENCES OF PHILADELPHIA. 851 



oped. The number of teeth is very constant and the dorsahnost are 

 not so greatly larger than the ventral as in A. alaskensis. On somite 

 X there are 115. Abdominal imcini are precisely similar/but^owing to 

 maceration the number on a torus is uncertain. 



This species was taken at station 4,227 OAly, in Behm Canal, the depth 

 being 62 fathoms and the bottom of dark green mud with fine sand. 



A small portion of tube present is rather elastic and springy'and is 

 coated externally with a layer of brownish flocculent sediment. 



Melinna cristata sp. nov. (Plate XLIV, figs. 9 and 10.) 



The single example representing this species closely resembles M. 

 cristata (Sars) Malmg., from which it differs especially in the more finely 

 denticulated post-branchial membrane as well as in the much larger 

 size and greater number of segments. 



Although the posterior extremity is missing and the last one-third of 

 the body is strongly spirally coiled, the specimen measures approx- 

 imately 73 mm. long, exclusive of the branchiae. At its widest part the 

 thorax measures 3 mm., while the abdomen has a maximum width of 

 2 mm. The 17 setigerous thoracic segments have a length of 12 mm. 

 and the fifty-five remaining abdominal segments 61 mm. 



The prostomium or cephalic plate is a broad, short plate with a 

 slightly convex crenulated anterior margin projecting freely over the 

 bases of the fourteen to sixteen tentacles. The latter have a uniform 

 diameter from base to end . The anterior and median ones are the largest 

 with a length of about one and one-half times the thoracic width and 

 about twice that of the posterior tentacles, which are scarcely as long as 

 the body width and about half the diameter of the anterior ones. On the 

 dorsal surface of the prostomium are the sensory folds, which are di- 

 rectly transverse. Beginning close to the lateral margins of the head 

 they meet at the middle line and bend slightly forward side by side. 

 Their dorsal surface is pigmented with a rich orange brown. Just in 

 front of them on each side is a small, slightly elevated pad. The much 

 folded upper lip is large and projects far beyond the mouth, just ante- 

 rior to which is a distinct glandular area. 



The lower lip is formed by the prominently projecting smooth margin 

 of the prostomium, which is indistinguishably united to the first setig- 

 erous segment. Dorso-laterally it forms a promineniwing anterior to the 

 firsttuftofsetse, whence it is continued caudally into a flange-like ridge 

 on each side of the thorax. Somites III and IV are well defined and to- 

 gether equal in length the single ring formed by the union of the prosto- 

 mium and first setigerous somite. The remaining thoracic segments are 



