312 LEIOCHONE (CLYMENE) EBIENSIS. 



about the same size. Both have an elevated ventral streak, which passes to the edge of the 

 funnel, and both have short, stiff, conical cirri, which in that from Montrose Bay are thirty 

 in number, whilst in the more beautiful specimen from the ' Porcupine ' there are thirty- 

 seven more acutely conical cirri. A slight anal cone is also present in the example from 

 the ' Porcupine,' but this is due to differences in contraction during life. Minute processes 

 surround the anal aperture. The firm rim or shelf from which the caudal funnel arises 

 is the same in both, and it has in front of it two unarmed segments with lateral glandular 

 areas. 



The hooks (Plate CIX, fig. 9, and Plate CX, fig. 1 a) are comparatively large in the 

 posterior region, the shafts are but slightly bent, the shoulder is moderately developed, and 

 the neck is long. Moreover, the form of the neck is diagnostic, since the prominence from 

 which the strong gular bristles spring is removed from the base of the main fang by 

 nearly its own length, the tuft curving to the tip of the fang and then above it. Whilst 

 the posterior outline of the neck (which is slightly bent backward) is smooth, that in front 

 has the bold prominence of the gular tuft, with the long, smooth sinus running to the fang 

 above it. The crown is not high, has four teeth above the main fang, the first standing 

 at an angle to the great fang, the neck is obliquely and the shaft longitudinally striated. 



Prof. Arwidsson, after a careful examination of this and other examples of Isocirrus, 

 was inclined to link them together as representatives of a single species, and perfect 

 specimens can alone remove all doubts. In the meantime the general outline of the hooks 

 of this large form and their minute structure warrant special notice. 



Genus CXXI. — Leiochone, Grube, 1868. 



Cephalic lobe much reduced, the margin variable. Distinct naked segments 

 posteriorly. Between the last and the anal cone are several rings and a smooth, short 

 part, with a long, slender ventral cirrus, or two, the dorsal edge being free. Well- 

 developed glandular bands on the anterior segments ; the triangle of the belt over the 

 ventral hooks. The ventral bristles of the anterior segments consist of more or less 

 reduced hooks, with hairs under the main fang. The anterior capillary bristles have 

 narrow wings and short, very fine hair-pencils. The points of the posterior bristles are 

 not wider inferiorly. The shaft of the hooks is curved. The external openings of the 

 segmental organs lie behind the rows of hooks. Free and straight tube. 



1. Leiochone (Clymene) ebiensis, Audouin and Edwards, 1844. Plate C, fig. 18; Plate 



CIX, figs. 10-10 b— bristle and hook. 



Specific Characters. — Anterior end pyramidal or somewhat clavate, with a pointed 

 frontal process. Dorsally, only a narrow median keel and two adjacent, parallel and 

 sharp ridges, represent the usual cephalic plate, the ends of the ridges appearing on each 

 side of the frontal process in an anteroposterior view. Between these and the keel are 

 the nuchal grooves. A dense series of minute dark eyes occur on the sides of the snout 

 dorsally, but disappear in front by passing ventrally where they extend forward to the 

 apex. Body from 5 to 6 in. in length, rounded, with a distinct mid-ventral ridge 



