THE BAENACLES IN THE U, S. NATIONAL MUSEUM. 



105 



ALEPAS PACIFICA, new species. 



Type.—Q?it. No. 28797, U.S.N.M. 



Type-locality. — Sea north of San Francisco, California, taken from 

 a jell}^ fish, March 26, 1894, Stanford University. 



The capituUim has thin walls, collapsing- in alcohol. The oceludent 

 margin is straig"htened, slightly protruding along the orifice, the carina! 

 margin regularly arched. The width of the capitulum is about two- 

 thirds its length. At the base of the orifice there is a pair of imper- 

 fectly calcified, rather indistinct white scuta. So far as can be made 

 out, each consists of a narrow band along the oceludent border, with 

 two narrow diverg-ent lateral lobes. The orifice is ample, occupying 

 a little more than half the length of the capitulum. It is continued 

 as a superficial slit in the- outer tunic nearly to the base. The integ- 

 ument is smooth, of a dull g-rayish-bufl' tint, 

 and, while somewhat thickened along- the dorsal 

 border, there is no keel or angle there. No 

 tubercles, hairs, or tactile organs of any kind 

 are visible. 



The peduncle is shorter than the capitulum, 

 oval in section, but collapsing in the alcoholic 

 specimens, tapering slightly toward the base of 

 attachment. Its integument is nearly smooth 

 and colored like the capitulum. 



Length of capitulum 36, greatest width 25 

 mm. Length of the peduncle 20, width in the 

 middle 11 mm. 



The mandible (Plate V, fig. 2) has six teeth, 

 counting the lower point. The upper tooth is 

 acuminate and curved; the rest are of the usual 

 sliape, the lower ones smallest. There is some 

 short pubescence upon the lower teeth and on the margin below them. 



The maxilla (Plate V, fig. 1) is peculiar. There is a single large 

 spine at the upper angle and a deep excavation of the edge below it. 

 The rest of the edge protrudes and is irregularly spinose, the spines 

 being very short. There is some fine and short pubescence at the 

 lower angle. 



The cirri are all .short, the first (Plate V, fig. 5) with shorter, more 

 lanceolate rami than the others. All have whorls of delicate bristles, 

 longer and more numerous on the anterior side (Plate Y, fig. 1, third 

 cirrus). The second to fifth cirri are of about equal length, the sixth 

 longer. The rami of cirrus i are composed of 6 and 7 segments, ii and 

 iii of S, iv and v of 10, vi of 10 and 12 segments. 



36. — ALEPAS PACIFICA, 

 NATURAL SIZE. 



