78 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.10 



Considering the abundance of O. nebulosa which has turned up at some 

 stations (coll. 1304-41), it would seem to have colonial habits, perhaps 

 forming extensive beds. 



Distribution. — O. nebulosa has heretofore been recorded only from 

 Monterey, California, in 65-71 fms (Moore) and Perlas Island, Pana- 

 ma, in 6-9 fms (Monro). The present collections originate largely from 

 off southern California and the outlying islands, but include also Guate- 

 mala, western Mexico, and Pacific Panama. The bathymetric range ex- 

 tends from the shallow littoral to depths of 172 fms. 



Onuphis microcephala, new species 

 Plate 3, Figs. 67-75; Plate 18, Fig. 339 



Collections. — Punta Cholla, Sonora, Mexico, intertidal (collected by 

 Mr. S. A. Glassell) ; 878-38 (3) ; 930-39 (1). 



The type collection (Punta Cholla) includes a long, 40 cm tube 

 (pi. 18, fig. 339) from which a complete individual was removed. The 

 tube is 15.5 mm wide, cylindrical, soft, limpid, thin, with a parchment- 

 like base and covered over with a thin layer of fine, white sand grains 

 and sparsely scattered coarser shell particles. The complete specimen 

 measures about 120 mm long but is more or less strongly contracted 

 though fixed in the tube ; the number of segments is about 250. The body 

 is broad, depressed, rapidly narrows anteriorly to a short, blunt end. The 

 anterior dorsum is marked with 5 or 6 reddish-brown, transverse stripes 

 across the middle of the peristomium and the first few setigers, but these 

 bands diminish in intensity and extent farther back. The prostomium and 

 the rest of the body are pale. The prostomial lobe has a pair of slight 

 smudges on either side near the posterior edge, and a pair of circular eye- 

 spots immediately behind and between the paired tentacles; rarely the 

 eyespots are not discernible. 



The prostomium and its occipital tentacles are small and short, com- 

 pared with those of nearly related species. The prostomium is broadly 

 rounded in front. There are 2 thick, ovoid, frontal antennae and a pair 

 of much thicker, oval, pale palpi ventrally. The occipital tentacles have 

 short ceratophores, with 4 or 5 rings; the distalmost ring is the longest. 

 The styles of the inner lateral pair are the longest, reach back to the 

 eighth setiger; the styles of the outer lateral and median tentacles are 

 short, about twice the length of the frontal antennae. 



The peristomial ring is about as long as the first setigerous ring at 

 the sides, but shorter at its middorsum. Its cirri taper, are slender, about 

 % as long as the prostomium. Its anterior margin is smoothly rounded. 



