ADMETELLA HASTIGERENS. 65 



length (about 1.5 mm.) about three fourths the width (2 mm.). Constricted 

 at the base. Bulging out on each side, a large rounded prominence which shows 

 a darkening but no evident eyes. The anterior margin is wide and nearly 

 straight, with no median incision. The ceratophore of the median tentacle 

 arises caudad of the middle; it is large, and on each side has a very conspicuous 

 extension from its base. Each lateral extension is connected with the cera- 

 tophore by a narrow isthmus beyond which it is swollen, conical, and projects 

 upward and forwards distally. Above the swollen portion adjacent to the 

 isthmus it is narrowed conically to a slender filament of moderate length; the 

 total length of the appendage is apparently less than twice the length of the head; 

 these appendages correspond to the tentacular scales noted by Mcintosh in 

 his description of A. longipedata and as corresponding to those in the Sigalionidae. 

 The lateral tentacles, or antennae, are broken off; each is inserted on the anterior 

 face near the ectal corner, and apparently projected directly cephalad; what 

 appears to be a portion of the style of one was found adhering to the border of 

 the mouth, this is a slender terete body ending in a slender filament not preceded 

 by an enlargement. The palpi are large, terete, and gradually acuminate, the 

 tips very slender and ending in a filament which seems to be easily caducous; 

 smooth; near 1 mm. thick at base and 8 mm. long, or six times the length of the 

 prostomium. (Plate 9, fig. 6). 



The peristomium is slightly exposed above as a narrow transverse fold 

 caudad of prostomium. The ceratophores of its parapodia are prominent. 



The metastomial somites are all distinctly differentiated; those of the 

 anterior and middle regions of a nearly uniform length (width in anterior region 

 near 3.4 times the length, in the widest middle region near 4.8 times), in the 

 caudal region decreasing conspicuously. Pygidium small, pointed. The ne- 

 phridial papillae arise at each ectal end of the ventral surface of the somite 

 at the middle adjacent to the parapodium rather than at the caudal edge, as more 

 usual, the caudal margin of the somite more or less extended immediately mesad 

 of the papilla; they begin on the sixth somite; the anterior ones are small, sub- 

 cylindrical structures somewhat narrowed distad and then a little flaring about 

 the terminal face, each extending caudad and a little dorsad into the inter- 

 segmental cleft; farther caudad the papillae become conspicuously, stouter, 

 decreasing again in the caudal region. 



The elytra are all missing. The elytrophores are mostly conspicuous, with 

 the usual somewhat ear-shaped scar. They occur on the second, fourth, fifth, 

 seventh, and alternate somites to the twenty fifth, then on the twenty seventh, 



