180 ODONTOSYLLIS FULGURANS. 



Moreover, on its convex edge it presents several wart-like papillae, but whether these are 

 due to imperfect preservation is uncertain. 



Head (Plate LIX, fig. 15) rounded, provided with two moderately elongated palpi, 

 which in the Zetlandic specimen seemed to be short, and three tentacles, the median, 

 which arises in front of the eyes, being the longest. Eyes four, large, purplish, the 

 anterior with lenses. In the Zetlandic example from deep water they nearly formed a 

 square. A Y-shaped groove divides the head into three regions. 



Body fully an inch in length with upwards of sixty segments, slightly tapered 

 anteriorly and more so posteriorly. A prominent papilla behind the head in the mid- 

 dorsal line. Of an orange hue throughout. De St. Joseph gives it 100 segments and states 

 that it is pale yellow in front and behind, reddish over the intestinal region, and with 

 whitish grains arranged along the dorsum. 



Proboscis with seven denticulations ; proventriculus long (to the' sixteenth segment). 



Posteriorly the body terminates in two caudal cirri with a slight median process 



between them (Plate LIX, fig. 16 a). When the tail is injured the two cirri in front of 



the truncated extremity bend backward and become somewhat longer than the others 



(Plate LIX, fig. 156). 



The feet are more prominent than in Autolytus and are distinctly bifid at the tip 

 (Plate LXX, iig. 11). The dorsal edge 1 passes outward with a slight curvature to the 

 two spines which just pierce the upper and outer angle, a deep groove occurring 

 beneath so as to split the tip vertically. The greater part of this lobe is occupied by the 

 strong, translucent bristles which have a slight curvature below the dilatation at the tip 

 of the shaft (Plate LXXIX, fig. 4), which is bevelled as in allied forms, and ends in a 

 point. The edge appears to be almost smooth. The terminal process is articulated as in 

 Autolytus, and shows a strong hook, and after a distinct interval, so as to be about the 

 middle of the curve, a smaller process. The bristles are proportionally larger than in 

 Autolytus, and their structure is diagnostic. 



The inferior lobe of the foot is more or less ovate, its bluntly-conical tip being less 

 prominent than the upper lobe. 



Claparede found this species at Port-Vendres, Pyrenees Orientales, and describes the 

 beautiful emerald lustre of its phosphorescence in daylight. A band of green shone along 

 each side of the body, and by-and-by broke up into points grouped at the bases of 

 the feet. 



Marenzeller's 0. virescens from the Adriatic, as De St. Joseph states, approaches this 

 species very closely, indeed, the structure of the head, the foot, pharynx, and other parts, 

 is almost identical, but he did not observe the second tooth on the terminal piece of the 

 bristles or notice the phosphorescence. 



De St. Joseph points out that the pharynx (proboscis) has ten teeth and ninety rows 

 of points in the proventriculus, and that the terminal pieces of the bristles are bifid, and 

 arranged as his excellent figure shows. He observed a transparent gland in the feet of 

 the middle region of the body, the function of which is undetermined. He found that it 

 developed directly, and that the eggs were violet. Moreover, after a precursor of a 



1 In one preparation what seemed to be a band of cilia coursed along the upper border of the 

 foot. 



