REPORT ON THE ANNELIDA. 
253 
the extremity also diverges in each case. The bristles are continued amongst the hooks 
to the posterior end of the fragment. The posterior hooks (PI. XVIIIa. fig. 11) 
decidedly differ in size, curves, serrations, and other points from those of Lumbrico- 
nereis fragilis. The spines are also pale throughout. 
In transverse section the body-wall of this species somewhat corresponds with 
Lumbriconereis abyssorum, having a comparatively large nerve-area, with a short and 
wide pedicle, while no neural canal is visible in the preparation. In the intestine are 
peculiar pear-shaped bladder-like structures with parallel granular folds. These may be 
either parasitic bodies or introduced with the food, probably the former. 
At first it appeared as if this form was only a variety of the common Lumbriconereis 
fragilis, but a consideration of all the points in its structure shows the desirability of 
separation. Verrill describes a species [Lumbriconereis opalina f with four eyes, and 
similar feet, but as he does not go into the anatomy of the dental apparatus or the bristles 
their relationship is uncertain. 
Lumbriconereis ehlersii, n. sp., var. tenuisetis (PI. XXXVII. fig. 9 ; PI. XVIIIa. 
fig. 12). 
ILabitat. — Dredged at Station 47 (off the American coast, midway between New 
York and Halifax), May 7, 1873 ; lat. 41° 14' N., long. 65° 45' W. ; depth, 1340 fathoms ; 
surface temperature, 42°'0; sea-bottom, blue mud. 
Like the rest this form is fragmentary, but it is larger than several of the foregoing, 
measuring about 48 mm. in length and about 3 '5 mm. in breadth anteriorly. 
It has much of the facies of Lumbriconereis fragilis, and as we are at present in doubt 
concerning the sexual and other variations, especially in regard to any change occurring 
in the form of the bristles in the respective sexes, some dubiety remains in connection 
with the subject. 
The head (PI. XXXVII. fig. 9) is less acutely conical than in Lumbriconereis 
fragilis, and is marked on the dorsum by numerous longitudinal pigment-streaks. These 
attain their maximum posteriorly, but yet do not show the distinct specks charac- 
teristic of the head of the previous species. There are also a few longitudinal streaks 
on the ventral surface, but no specks exist on the labial folds. No grooves occur on 
the snout, either dorsally or ventrally. 
The dental apparatus is dark brown, the maxillary region being large in proportion 
to the space occupied by the great dental plates (Figs. 20 and 22), the horny parts of 
which are small. The spathulate posterior region of the maxillse tapers distaUy. The 
left great dental plate has five teeth, the right five. Both lateral (anterior) plates are 
^ Report of U.S. Fish Commission, Invert. An. of Vineyard Sovrnd, p. 594. 
