200 PROCEEDINGS OF THE ACADEMY OF [May, 



anteriorly. Succeeding segments rapidly increase in length until by 

 XIII they are f as long as wide, becoming also subterete, strongly 

 convex below and somewhat flattened above. Pj'gidium unknown. 



Except the first (on II) the parapodia are larger than usual. That 

 of II consists of a minute notopodial setigerous tubercle and papilli- 

 form postsetal lobe immediately behind the base of the tentacular 

 cirrus, and a small neuropodium situated at the level of the notopodia 

 of succeeding segments. Succeeding parapodia have prominent 

 foliaceous postsetal lamellae on both rami, but with the appearance of 

 crochets on VIII the neuropodium becomes much reduced. 



Gills begin on VIII or sometimes IX and continue to XXVIII, at 

 least, arising from the dorsum in contact with the base of the noto- 

 podium; form subcylindrical, rather short, apparently never long 

 enough to meet across the back, but their bases connected or nearly 

 connected by a low, ciliated, delicate, transverse fold. 



Setae of II few and very small, the notopodials only 3 or 4, very 

 slender and delicate, the neuropodials 6 or 8, short, slightly curved 

 and narrowly bilimbate. Succeeding notopodial setae rather con- 

 spicuous and numerous for the genus, anteriorly about 18-20, arranged 

 in 2 rows, the dorsalmost (fig. 19a) longest and rising prominently 

 over the back, narrowly bilimbate, very slender and little curved, the 

 ventralmost (fig. 196) much shorter, often doubly curved, with much 

 broader wings and acute awn-like tips. Toward the middle of the 

 body the number decreases and all the setae become more slender and 

 elongated. Anterior neuropodials also in two vertical rows of usually 

 6 or 7 each, all smaller and more strongly curved than the notopodials . 

 Crochets appear abruptly in the nem-opodium of VIII and never, so far 

 as observed, are accompanied by capillary setae. Anteriorly there are 3, 

 farther back 5 or rarely even 6. They are colorless, slender, with a 

 long acute beak and slender erect accessory tooth and are enclosed 

 distahy in a delicate hood, composed of a pair of well separated guards 

 (fig. 22). On somite VI there are almost invariably three (in only 

 one case out of many fovu-) pale yellow spines in a strictly vertical row 

 (figs. 20, 21). They are straight, slightly enlarged at the end where 

 they bear a principal and an accessory blunt, straight, conical tooth, 

 below which, on the posterior face, is a half-round sheath ending in a 

 free border on the side of the small tooth and forming a flange encircling 

 the base of the large tooth on the opposite side (figs. 20a and 21). On 

 the anterior side of these spines and alternating with them are a corre- 

 sponding number of broadly bilimbate setae, and a group of 3 or 4 

 similar and perfectly straight setae lies just dorsad of the spines. Ven- 



