250 THE ANNELIDA POLYCHAETA. 



cles being in contact with or embraced by the latter. The prostomium is deeply 

 divided by a median incision into two lobes, the furrow continuing distinctly 

 to the base of the median furrow ; each lobe is oblique and is divided by a weak 

 furrow into a larger inner and a smaller outer division. The tentacles are 

 arranged in a semicircle in contact with the peristomium. The median tentacle 

 has the apical portion broken off; as it is, it reaches somite VI; it is smooth, 

 without annulations or wrinkles. The inner paired tentacles reach somite 

 VII; they are a little more slender than the median and are strongly tapered; 

 each has a wholly smooth proximal division embracing more than two thirds 

 the total length, followed by three short joints, of which the first is more vaguely 

 separated, the other two distinctly so. The outer paired tentacles, more slender 

 than the inner ones, are very short, reaching only to somite II; each ends in 

 two or three short articles, the longer proximal division being wholly smooth. 

 (Plate 58, fig. 5). 



The first somite, or peristomium, is dorsally about equal to the succeeding 

 two and a half somites. Dorsally the anterior margin is smooth and evenly 

 incurved and the dorsal surface is smooth. Laterally, where meeting the outer 

 end of the prostomial lobes, there is a pronounced incision and furrow. The 

 lower lip has its margin evenly incurved; its surface is wholly smooth excepting 

 for two sulci which cross it longitudinally, one each side of the middle. 



The second somite is distinctly set off above between the cirri and ventrally, 

 but, as usual, is wholly fused with the first laterally. Above, it is shorter than the 

 third somite. Cirri are short and slender subulate appendages which do not 

 quite reach the anterior margin of the peristomium. Proximally each cirrus is 

 smooth, while distally, over more than half the length, it is annulate, the annuli 

 being short and only moderately distinct. (Plate 58, fig. 6). 



The third and succeeding somites bear parapodia. They are regular and 

 undivided excepting that the more anterior ones are each crossed above by a 

 weak furrow separating off a much shorter anterior division. In the widest 

 part of the body (near somite XII), the somites are about ten times as wide as 

 long. Somites are strongly arched and are nearly smooth; from the seventh 

 caudad they have a sharply impressed median longitudinal furrow. Ventrally 

 the somites are but slightly convex; they are. crossed longitudinally by a 

 pronounced neural furrow. From the region of the twelfth somite the body 

 narrows strongly cephalad and more gradually but decidedly caudad. The 

 pygidium in the type appears to have been broken off so that its character and 

 that of the anal cirri cannot be given. 



