AUTOLYTUS TORQUENS. 173 



It bears two pairs of tentacular cirri which are shorter and more slender than 

 the tentacles ; they are composed of distinct short articles and may appear some- 

 what moniliform; the dorsal cirri reach to the fifth somite, the much shorter 

 ventral ones to the third. 



The second somite is setigerous, the process being like that of succeeding 

 somites. It is dorsally more elevated than the first. It bears a pair of dorsal 

 cirri of nearly the same form as those of the immediately succeeding somites 

 and but little longer. Dorsally it presents an elevated area that protrudes for- 

 ward as a characteristic triangular tongue, which is truncate anteriorly. The 

 third and fourth following somites are similar to the second, but are more highly 

 arched, the depth of the anterior division of the body being greatest through 

 the last two of these. The somites are weakly convex ventrally. All somites 

 distinct and entire. In the second division of the body the somites continue 

 to increase in depth over about twelve somites and then decrease gradually 

 caudad. The anal cirri are short, very narrowly elHptic in outline. All somites 

 of the body are crowded with eggs, which occur also in the bases of the parapodia. 



The anterior parapodia are short and cylindric, distally shortly, subconically 

 rounded. The notocirrus is attached well above the base on the side of the 

 somite. The cirrophore is short and much broader than the style, which is 

 exceptionally long, extending far beyond the tips of the setae and being nearly 

 three times the length of the parapodium; the style is slightly tapered and its 

 annuli are usually moderately distinct. The setae are usually twelve in number. 

 The parapodia of the posterior division of the body are short, and very deep as 

 compared with the thickness in the anteroposterior direction. Each presents 

 two very distinct divisions, a shorter, stouter dorsal one bearing the numerous, 

 fine, simple setae and a much more slender and longer, subcylindrical ventral 

 one diverging ectoventrad from the other and bearing the composite setae. 

 The notocirrus is attached near the distal end of the upper division. The cirro- 

 phore is short and not thickened. The style is more than half the length of 

 the simple setae. (Plate 19, fig. 5, 6). 



The composite setae of a typical parapodium of the middle region of the 

 body are twelve in number, or near that, those of a series decreasing in length 

 from above ventrad as usual. In each the shaft is moderately curved, with the 

 concavity ventrad, and abruptly enlarged at the distal end to form the socket. 

 The distal edge of the socket on each side is moderately oblique and finely den- 

 tate. The distal piece is of the usual general form. It is distally bidcntate, with 

 the teeth moderately large and scarcely differing in size, or, if any different, the 



