LYCASTIS QUADRATICEPS. 373 



while to put on record the few additional facts I have been able 

 to gather from a study of the material at hand. 



The species might almost be called minute, considering the 

 generous dimensions of most of its allies. It seldom exceeds 18 

 mm. in length and one millimeter in transverse diameter, including 

 the parapodia, but not the setae. While of a general cylindrical 

 form and nearly uniform diameter throughout, there is a fairly 

 marked tapering in the caudal region toward the small rounded 

 pygidium which bears a pair of short, conical anal cirri (Fig. i). 



As in all species of Lycastis the feet are uniramous throughout 

 the series, a very small tubercle and an acicula representing the 

 dorsal ramus. The dorsal cirri differ from those of most species 

 of the genus in being diminutive instead of large and foliaceous. 

 Each parapod is armed with a single aristate seta representing the 

 dorsal fascicle, and a ventral fascicle of one aristate seta and three 

 to five falcate ones. The prostomium is characteristically short 

 and broad ; the antennae are minute, and the tentacular cirri all 

 short and stumpy, the stylode tapering rapidly from a short, 

 thick ceratophore. The palpi are large for the size of the worm. 

 The four eyes are black, those on the same side placed close 

 together. 



In specimens cleared with oil and mounted entire in balsam the 

 internal structures can be made out in considerable detail (Figs. 

 i and 2). No paragnaths have been detected, nor indeed are 

 they known to occur in any species of Lycastis. The jaws are 

 plainly visible and are armed with four or five teeth. The ali- 

 mentary canal has the usual divisions, the only part deserving 

 especial mention being the glandular stomach, which lies in 

 somites VII. and VIII., or in VIII. and IX., or even extends 

 into X. This "stomach" is thick-walled, exceeding in this 

 respect even the oesophagus, and the lumen is strongly encroached 

 upon by the large rounded protuberances which stud its inner 

 surface. In sections these protuberances are seen to be composed 

 of a syncytial mass containing numerous darkly staining nuclei, 

 but no cell-boundaries have been detected. This is clearly a 

 portion of the lining epithelium of the alimentary canal, but of 

 peculiar and specialized character. In addition to the nuclei 

 there are very many minute bodies, some round and some 



