412 PROCEEDINGS OF THE ACADEMY OF [JlUie, 



stand out clearly. The larger papillae are chocolate-brown, recldish- 

 brown, yellowish-brown, partly brown and partly yellow, or, in strik- 

 ing contrast, white, and it is very seldom that two adjacent ones are 

 of the same color. 



One specimen, type, Sta. 3,702, Sagami Bay, 31-43 fms. 



L. branchiferus and L. chitoniformis are evidently closely related to 

 L. giganteus Ivirk from New Zealand which, according to Thomson, 

 possesses essentially similar branchiae and dorsal tubercles, and exhibits 

 additional features of resemblance in the elytra and sette. In a number 

 of respects all three depart from the typical species of Lepidonotus and 

 might very properly be segregated as a distinct generic group. Lepi- 

 donotus branchiata (Treadwell) from Porto Rico possesses similar 

 branchiae, but the setae and elytra are quite different and no reference 

 is made in the description to dorsal tubercles. 



Lepidonotus caelorus sp. nov. (PI. XXIII. fig. 12.) 



The form is, as usual in the genus, short and compact, but much 

 more slender than the 2 species just described; the largest specimen 

 measures 25 mm. long, exclusive of the tentacles and anal cirri, and 

 8 mm. wide to the tips of the setae. Number of somites 26. 25 bearing 

 setigerous parapodia, and 12 elytra. Ventral surface smooth, with 

 nephridial papillae from ^TII to XXV inclusive; all but the first are 

 prominent and tubular and project freely caudo-laterad. 



Prostomium slightly wider than long, though the continuation of 

 the peaks into the bases of the lateral tentacles gives it a somewhat 

 elongated aspect. Eyes normall}' 2 pairs, which have coalesced in 

 the type; the posterior near the caudal end of the lateral surface, but 

 not concealed by the nuchal fold, looking latero-dorso-caudad, heavy 

 black, circular; the anterior lateral, at the point of greatest width, 

 looking latero-dorsad, larger than the posterior and elliptical or crescen- 

 tric, black. 



Except the palpi the cephahc appendages are very easily displaced, 

 and the median tentacle is present in the type alone. Its total length 

 is about 5 times the head, of which ^ is made up of the basal piece and 

 yV of the filamentous tip; l^asal piece constricted at the middle, the 

 proximal portion more opaque and smoother; style slender throughout 

 and tapering to a slightly subterminal enlargement, beyond which it 

 diminishes suddenly to the filiform tip. The lateral tentacles are 

 more often preserved and vary considerably in length. They have 

 the same general form as the median tentacle, but are longer and 

 decidedly more slender, with the subterminal enlargement scarcely evi- 

 dent, and the filiform tip longer (up to ^ of the entire length) ; the basal 



