POLYOPHTHALMUS PICTITS. 23 



anterior end, in the presence of the ventral groove between them, the lateral groove above 

 them, and the form of the caudal process and its papilla?. 



The body is about an inch in length, with about twenty-eight setigerous segments, 

 rounded dorsally and grooved ventrally, tapered at each end, especially posteriorly, 

 where it contracts gently to the abruptly diminished caudal process, which forms a short 

 cone with a few short terminal cirri (Plate LXXXVIII, fig. 2). Dorsally the body is 

 marked by about twenty-eight or thirty transverse brown bars, with a fine dusting of the 

 same pigment between and beyond them. These bars appear to have a definite position, 

 a line drawn from their extremities striking the middle of each space between the lateral 

 pigment-touches (so-called eyes). The densest dusting of pigment appears to be on the 

 terminal regions anteriorly and posteriorly, the base of the caudal process, indeed, having 

 a continuous brown blotch. The dorsal surface in life is ciliated. 



The digestive system has a short proboscis, cup-shaped in extrusion, and a trans- 

 versely grooved region occurs behind the lower lip. Claparede describes a pair of blind 

 appendages of the canal, the ends of which reach the ninth segment. He also mentions 

 an orange-red dorsal blood-vessel, and a ventral trunk on the ganglionic chain, each 

 connected with the other by a lateral branch in every segment. The branch in the eighth 

 segment presents a large dilatation on each side, the blood thus passing from the dorsal 

 to the ventral trunk. A sub-intestinal vessel, and a lateral vessel on each side in the line 

 of the bristle tufts, complete the main series. 



De Quatrefages (1850) gave an account of the circulation of this genus, describing 

 and figuring a posterior auricle and a pair of ventricles in front. The red blood flows 

 forward in the intestinal lacunae, and enters the auricle, part going by the dorsal trunk to 

 the head, then the lateral organs (ventricles) contract and drive it into the ventral trunk. 



When the line of transverse section passes through a pigment-speck (eye), it is found 

 to consist of a capsule with dark pigment internally, and distally of a pale region, which 

 may perform the functions of a lens. The organ is situated on the upper edge of the 

 ventral swelling, just outside the upper insertion of the oblique muscle (Fig. 96). 



De Quatrefages shows a distinct nerve-twig going to the organ. 



Externally these pigment-spots occur in the groove above each ventral longitudinal 

 muscle, and are fully twenty in number, though none of the preserved examples has a 

 complete series. 



Though at first sight the bristles (Plate C, fig. 11) are not evident, yet they occur in 

 a rudimentary form in each segment, forming minute tufts of simple tapering bristles, 

 best seen towards the caudal region, where the four or five last tufts, as Claparede 

 showed, are double. 



Reproduction. — De Quatrefages (1850) thought the reproductive period was in spring, 

 and that the elements escaped by a canal placed above (on the dorsum) the terminal 

 portion of the intestine, and opening into it. 



Claparede described the eggs as ellipsoidal, and thought they escaped partly through 

 the anterior region of the body and partly by the vent, for he found that they entered the 

 gut by a special aperture in the twenty-fourth segment. 



Lo Bianco (1909) notes that the spawning period might extend throughout the year 

 — at any rate, from March to October, 



