1910.] NATURAL SCIENCES OF PHILADELPHIA. 393 



and more strongly compressed than usual in the family. For the 

 most part they project strictly laterad and their length is two-fifths to 

 two-thirds the width of the somites. Though conspicuously biramous 

 the rami are closely united and the interamal cleft is little developed. 

 Neuropodium (PI. XXXIII, figs. 106 and 107) deep and compressed, 

 scarcely tapered, ending in a thick, obliquely truncate, notched acicular 

 process, surrounded above, behind and below by a perisetal fold, the pos- 

 terior part of which is well developed as a broad, deep, oblique mem- 

 brane with the margins entire, the dorsal and ventral portions being less 

 developed, discontinuous and bearing small marginal sensory papillae. 

 Notopodium (figs. 106 and 107) very much smaller than neuropodium 

 and slightly overlapping its posterior face, subcorneal or prolonged 

 mammilliform, receiving the tip of the aciculum in the apex and bearing 

 a spreading fascicle of setse. On the dorsal side of its base is a large 

 opake hemispherical swelling which bears the ventral ctenidium 

 except on anterior parapodia. 



Notocirrus rudimentary throughout length of piece — a minute papilla 

 (PI. XXXIII fig. 107) on the ventro-lateral part of a rather prominent 

 opake swelling representing the dorsal tubercle, ceratophore and elytro- 

 phore combined, on the ventral side of the projecting end of which is 

 a peculiar scale-like ensheathing lamina bearing a ciliated area proba- 

 bly representing the dorsal ctenidium. Between the dorsal process 

 and the parapodium is the usual deep bay. Ctenidia are slightly 

 developed and obvious on only certain parapodia. The dorsal and 

 ventral have already been mentioned ; the intermediate one (fig. 107) — 

 no better developed — occurs about midway between the others. Neuro- 

 cirri arise from near base of parapodium from a small cirrophore and 

 reach base of ventralmost seta?; basal half of style enlarged and with 

 a dorsal concavity, distal half slender and divided into three incom- 

 pletely differentiated subequal segments. First four parapodia 

 directed progressively more forward. On II and III the neurocirri 

 are longer, that of II reaching slightly beyond the end of its parapodia. 



Elytra borne on II, IV, V and alternate segments to at least XXI, 

 beyond which I am unable to distinguish which segments have borne 

 elytra. Only the first four pairs and the eleventh elytra are attached, 

 beside which there are a number of loose elytra in the bottle. Those in 

 place fail to meet medially, leaving a large part of the dorsum uncov- 

 ered and the eleventh pair is especially small, but all curve down the 

 sides quite to the parapodia. First pair circular, the next few oblong 

 with the medial end boldly rounded and the anterior border slightly 

 concave (Pi. XXXIII, fig. 108), the posterior ones nearly equal-sided 



