280 THE ANNELIDA POLYCHAETA. 



anterior view. It is depressed anteriorly between the bases of the frontal 

 tentacles and is vaguely, finely, transversely wrinkled above between the poste- 

 rior tentacles and the peristomium, and there is a weak median longitudinal 

 sulcus between base of median tentacle and the caudal margin. The bases of 

 the tentacles are arranged in a circle. The frontal tentacles are subcorneal, 

 distally well-rounded processes, also constricted at very base, diverging from 

 each other moderately and separated at their bases typically by about half 

 their diameter; the prostomium beneath these is but slightly carried forward. 

 The frontal tentacles have the usual long, stout ceratophores bearing the slender, 

 finely attenuated styles. The ceratophores are all widest near the middle, 

 narrowing toward both ends, and are composed of numerous very short annuli 

 between which the constrictions are not deep or conspicuous. The tentacles 

 of the anterior pair reach a little caudad of the middle of somite II. In these 

 the style is twice as long as the ceratophore and is uniformly narrowed distad; 

 the ceratophore is composed of seven very short annuli, of which the most distal 

 is longest. The tentacles of the posterior pair reach to somite VII. In these 

 the style is between five and six times as long as the ceratophore. The cerato- 

 phore is fully a third longer than that of the anterior pair and is much stouter; 

 it consists of nine or ten very short articles, of which the ultimate is longer than 

 the immediately subjacent ones, as usual. The median tentacle is much shorter 

 than the posterior laterals, reaching only to about the beginning of the third 

 somite. In this the slender style is nearly three times as long as the ceratophore. 

 The ceratophore is much more slender and only about three fourths as long as 

 that of the posterior laterals; it is composed of five articles. (Plate 49, fig. 5). 



The peristomium laterally continues the general outline of the prostomium, 

 widening caudad. It is more abruptly elevated dorsally. The anterior margin 

 above is angularly produced forward at the middle. Laterally the anterior 

 margin is nearly straight. On each side a weak furrow runs back obliquely 

 caudoventrad. The lower lip is strongly elevated; it is set off on each side by 

 a depression running obliquely caudomesad from the outer anterior angle; its 

 anterior margin is smooth, and widely, moderately incurved mesally. The 

 tentacular cirri are short, slender, acuminate processes attached near the ante- 

 rior margin and not reaching to base of the posterior tentacles. (Plate 49, 

 fig. 5). 



The first two metastomial somites are strongly arched dorsally, the third i 

 decreasing in height caudad to the distinctly lower level of the immediately] 

 following somites. The peristomium is longer than the first podous somite. 





