1909.] NATURAL SCIENCES OF PHILADELPHIA. 269 



from the sides of which project a pair of small lobes probably repre- 

 senting palpi; these lobes and the ventral surface of the lip are pale, 

 in sharp contrast to the nearly black surface of the remainder of the 

 head. The posterior or peristomial half is a simple naked ring. 



Several of the immediately succeeding metastomial segments are 

 very short, but those following become gradually longer until they 

 are one-fourth or one-third as long as wide, but caudally they again 

 become very short and crowded and end in a simple pygidium with 

 rather large central anus. 



The first metastomial segment (II) bears a dorsal pair of simple 

 terete branchial filaments or notocirri which in extension are smooth 

 and three or four times as long as the head and in contraction trans- 

 versely wrinkled and much shorter ; ventral to these is a pair of usually 

 shorter and thicker neurocirri or prehensile tentacles which are grooved 

 along the ventral face and transversely wrinkled. The latter vary 

 much in length in different specimens, being in some less than the 

 diameter of the body, in others more than three times the diameter. 

 Notocirral branchiae also occur on from seven to ten next succeeding 

 segments (III to IX or XII). Of these the first three are commonly 

 larger than that on II, and because of the dorsal position of the latter 

 and the extreme shortness of the segments lie at successively lower 

 levels in a nearly vertical series; the fifth and succeeding pairs arise 

 immediately dorsal to the notopodial setse and on the same level as 

 the fourth pair. Specimens from the vicinity of Monterey Bay have 

 the fifth and rarely the sixth pair nearly as long as the more anterior, 

 but on those from San Diego they are always much shorter like the 

 remaining more caudal pairs, the last of which are usually mere 

 rudiments. 



Parapodia very small, lateral notopodial and ventro-lateral neuro- 

 podial tubercles separated by a small interval. Small tufts of notopodial 

 and neuropodial setse begin on II. On from eight to eleven segments 

 they are all slender, finely serrate setse, most numerous and longest in 

 the notopodia, in which they may be as long as their segment or longer. 

 At from IX to XII two stout yellow spines, bifid and hooked at the 

 end, appear in the neuropodium and a few segments caudad similar 

 ones in the notopodium. They may be accompanied by and alternate 

 with two or three minute capillary setse, but by about XX and all 

 through the middle region spines alone are present, from two to four 

 occurring in each fascicle and the neuropodial (PL IX, fig. 44) being 

 decidedly stouter with the terminal prong slightly hooked, flattened 

 and excavated. Notopodials straighter, less hooked and more flat- 



