156 SPH^JROSYLLIS HYSTRIX. 



being the wider apart. In addition, a small pigment-speck is situated internal to the 

 base of the anterior tentacles. 



Body 10 mm. long, about equally narrowed anteriorly and posteriorly, and composed 

 of about fifty bristled segments, but the condition of the posterior end is doubtful. It 

 terminated in two rounded lobes, but as the last foot and bristle-bundle projected from 

 the outer side of each lobe, the condition is unusual and probably indicates injury. 



In the foot (Plate LXX, fig. 2) the dorsal cirrus is short and stout, slightly tapered 

 towards the tip, and composed of nine to twelve segments at the anterior third, but the 

 number apparently diminishes posteriorly. The setigerous region is comparatively long 

 throughout the greater part of the body, and viewed from above is nearly cylindrical, or 

 with a forward curve, and in some slightly narrowed at the base. In lateral view a 

 slight hollow occurs below the spine superiorly, and then the margin slopes inward. The 

 region is thus bifid at the tip. Each bears a projecting tuft of somewhat strong bristles 

 of the ordinary type (Plate LXXVIII, fig. 10), the bevelled end of the shaft being 

 smooth, and the comparatively short terminal piece having a simple hook distally, the 

 figure representing one of those with shorter tips from the middle of the body. 



The anterior feet have bristles with more slender shafts and longer terminal pieces, 

 the posterior stouter shafts and shorter terminal pieces. The tip of the spines in some is 

 bent and projects slightly beyond the surface. The ventral cirrus is bluntly rounded at 

 the tip and in shape broadly lobate. 



This form is distinguished by the comparative shortness of the body, the short but 

 distinctly moniliform dorsal cirri, by the lobate form of the ventral cirri, and the simply 

 hooked terminal pieces of the bristles. It has certain resemblances in the shortness and 

 marked moniliform condition of the cirri to the Syllis scabra of Bhlers. 1 



Genus XLVII. — Sph^rosyllis, Claparede, 1863. 



Cephalic and peristomial segments coalescent. Palpi small, continuous with the 

 head, fused dorsally. Tentacles (three), tentacular cirri (two), and dorsal cirri short, 

 enlarged at the base. Eyes usually four. Body comparatively short, beset with papilla?. 

 First segment with a single tentacular cirrus on each side 2 , and bristles. Pharynx with a 

 single tooth ; proventriculus short. Ventral cirri short and filiform. Xo alternation of 

 generations (Claparede). Ova borne on the ventral surface. 



1. Sph^rosyllis hystrix, Claparede, 1863. Plate LIX, figs. 3, 4, 8; Plate LXX, fig. 1 



foot; Plate LXXVIII, figs. 11-13— bristles. 



Specific Characters. — Head with the palpi tapering in front. Eyes four, red, the 

 anterior pair having lenses. A median and two lateral tentacles much enlarged at the 



1 ( Borstenw./ i, p. 244, pi. xi, figs. 1—3. 



3 Claparede considers the pair on the united cephalic and peristomial segment tentacular cirri, 

 whereas Ehlers gives five tentacles to the head. 



