550 PROCEEDINGS OF THE ACADEMY OF [July, 



The peristomium is fused with the prostoniiiim above and the second 

 somite below, where also it is produced forward as a rather prominent 

 median lip. In complete sexually mat\n'e worms there are from loO 

 to 160 somites, of which all but 59 or 60 constitute the posterior or 

 genital region. Especially in the anterior region the segments are well 

 defined, smooth and terete, increasing in length to about XXX, and 

 in width more gradually to XL, where they are about 3 times as wide 

 as long; from that point to IJX or LX they remain nearly unchanged 

 in proportions or even somewhat contracted, except when distended 

 with ova or sperm, when they suddenly expand. In immature speci- 

 mens this change does not take place. At this point there is internally 

 a strong development of radiating muscles to which the constriction is 

 due, and which form a Ijar to the movement of the genital products for- 

 ward. On the other hand, the muscles of the body w^alls are somewhat 

 Weakened and one specimen is actually broken in two exactly at this 

 point. This species, therefore, presents a condition similar to that 

 described for Goniada foliacea, which it otherwise closely resembles in 

 many respects. The posterior region is somewhat depressed, an ap- 

 pearance that is much exaggerated by the prominence of the parapodia, 

 especially as the body decreases in width posteriorly. In only one 

 specimen is the caudal cirrus preserved ; it arises below' the anus and is 

 slender, tapering, and as long as the last 9 segments. 



Anterior to XXXIII or XXXIV the parapodia are uniramous, be- 

 hind that point biramous. The former (fig. 45) consist of an elongated 

 neuropodium terminated by a presetal lobe divided by a deep cleft into 

 slender, nearly conical dorsal and ventral lingulse and an undivided 

 presetal lobe of similarly slender form and nearly equal length. The 

 ventral cirri are prominent, with swollen bases united to the ventral 

 margin of the neuropodiimi and followed by a slight constriction, be- 

 yond w^hich is a short conical style. Dorsal cirri arise a little above and 

 behind the neuropodium. They have prominent but generally rela- 

 tively slender bases and broadly ovate foliaceous distal portions bent 

 abruptly dorsad. Beyond a gradual increase in size of all parts, espe- 

 cialh'- the dorsal cirrus and postsetal lobe, relatively little change takes 

 place from before backward. The base of the dorsal cirrus is relatively 

 thickest from X to XX. On the first two parapodia the presetal 

 lobe is undivided and the postsetal altogether absent; on the next 

 3 the latter increases to its normal proportions. 



At XXXIII or XXXIV the notopoclium appears somewhat suddenly 

 and immediately bears setae. It consists of an acutely conical presetal 

 lobe and a minute rather ventral postsetal tubercle and is nearly half 



