290 THE ANNELIDA POLYCHAETA. 



S., long. 78° 18' W.). Depth, 2,845 fms. Bottom of fine dark brown infusorial 

 mud. Bottom temp. 35.2° F. About fifteen tubes, in part with animals in 

 situ, were secured 21 November, 1904. 



Off Peru: Sta. 4666 (lat. 11° 51' S., long. 84° 20' W.). Depth 2,600 fms. 

 Bottom of fine grey radiolarian ooze. Bottom temp. 34.9° F. Two specimens 

 in tubes taken 18 November, 1904. 



This species is close in general structure to 0. pachytmetna. It differs 

 clearly, however, in a number of features. It contrasts in its decidedly greenish 

 color, and equally conspicuously in its very much shorter somites. It differs 

 uniformly in having the branchiae begin on the seventeenth parapodia instead 

 of on the sixteenth. The ceratophores of the tentacles lack the narrowing 

 towards both ends from the middle region characteristic of pachytmema, these 

 being strictly cylindrical, or with the sides at least not curved longitudinally. 

 The palps are more conical. The carrier-plates of maxillae I are relatively 

 broader, not incurved anteriorly, and have the thickened area extending to 

 the caudal incision instead of only part way, and the narrowed distal fang of 

 the blades relatively shorter. Maxillae II have twelve and thirteen teeth 

 as against ten. The mandibles have the masticatory plates more prolonged 

 caudad along the median line and the stems longer. The pectinate setae 

 differ decidedly in form, the distal blade being very much longer and narrower. 

 The lower prong in the crochets is longer and straighter. 



From 0. ehlersi Mcintosh, which it also approaches, it would seem to 

 differ decidedly in general form, being much shorter and broader, its maximum 

 observed length being 86 mm., with a maximmn diameter of 3.4 mm., whereas 

 in ehlersi the average length is 170 mm. and the width 2.5 mm. The carrier- 

 plates of maxillae I differ in not being narrowed anteriorly and the blades in 

 having a shorter and a more abruptly narrowed distal fang. The teeth" of 

 maxillae II are twelve and thirteen instead of ten; and the teeth of maxillae III 

 are eight on the left side and eleven on the right in place of nine on both sides. 

 The pectinate setae have the distal blade clearly relatively longer and more 

 slender. The branchiae would seem to be more strongly developed. 



Onuphis lepta, sp. nov. ^ 



Plate 45, fig. 1-7; Plate 46, fig. 3-12. 



The general color is brown, without definite markings excepting a paler, 

 ventral neural fine which is ordinarilv traceable over much of the length. The 

 appendages are scarcely paler. 



' Xeirris, slender. 



