OBTAINED DURING THE CRUISE OF H.M.S. ' VALOROUS.' 509 



about twenty in number on each side) are fragmentary, and appear in process of develop- 

 ment, as they scarcely exceed in length the diameter of the body. The long anterior 

 crotchets (PL LXV. fig. 19) slightly differ (in curves) from those of C. infimdibuliformis, 

 while the posterior hooks (fig. 18) still more diverge, a comparison with one from the 

 same region in the former being made by referring to fig. 17. Whether this is the 

 Chone Duneri, Mgrn., or another species, the brief remarks and somewhat unsatisfactory 

 figures given by the author prevent determination. The posterior hooks especially 

 disagree. 



The remarkable differences in the structure of the muscular system which distinguish 

 Euchone and Chone, on the one hand, from Sabella and Dasy chone on the other, are like- 

 wise associated with corresponding differences in regard to the arrangement of the nerve- 

 cords. The fasciculi of each dorsal and ventral longitudinal muscle in Chone infundi- 

 buliformis form a complex double spiral in transverse section ; while in Euchone the 

 dorsal also form a double spiral, less elaborate than in the foregoing, and the ventrals 

 each form a simple spiral. The nerve-trunks in both are much more closely approximated 

 than in Sabella and Dasychone. 



Serpula ? A fragmentary tube of a minute, shining, quinquecostate species, with four 

 transverse ridges anteriorly, and irregularly twisted ; from Station 11, 1860 fathoms. 



Ditrypa gbxenlandica, n. sp. (Pi'oc. Roy. Soc. vol. xxv. no. 173, p. 219, woodcuts 1 & 2.) 

 Station 12, 1450 fathoms, on Globigerina-ooze and stones. 



Kg. 1. 



a. Tube of Ditrypa grcenlandica, enlarged, b. The aperture, still more highly magnified. 



The tube is about half an inch in length, not much thicker than a thread, and curved 

 from end to end like a bow (see woodcut, fig. 1, a). It tapers very gradually from the 

 anterior to the posterior end, contrasting in this respect with the more decided diminu- 

 tion in D. arietina. The oral aperture (fig. 1, b) forms a smooth and slightly constricted 

 rim, which is narrower than the tube almost by the depth of the ridges. The latter are 

 eight in number, and run from the anterior to the posterior end of the tube, though, it 

 must be added, none of the specimens are quite perfect. It differs from any other 

 Ditrypa known to me in its slender form and the well-marked longitudinal ridges. In 

 the most perfect specimen the latter coalesce to some extent posteriorly, so that the tip 

 of the tube is somewhat quadrangular. 



Spirorbis bobealis, Daud. Godhavn Harbour, 5-20 fathoms. Tube only. 



Spirorbis verruca, Pabr. Station 5, 60 fathoms. Tube only. 



Spirorbis spirillum, L. Station 5. 



SECOND SERIES. — ZOOLOGV, VOL. L 3t 



