318 University of California Publications in Zoology. [Vol.6 



have a fifth pair of feet which are nol fully formed. According 

 to Farran (1908, p. 35), the presence of a fifth pair of feet in 

 immature animals of this genus is no evidence that they are 

 males; but 1 cannot see that this is the case, at least in the avail- 

 able material. 



Length: Adult females, 5.2 mm. 



Coloration: Red pigment is found in the body between the appendages, 

 in the eye, mouth-parts and feet, distal half of anterior antennae, and in 

 the intestine. 



Occurrence: Station 1249. tow at, and vertical from, 325 f.. sounding 

 370 f., July 11, 190(3; station 1315, tow at, and vertical from, 320 f., sound- 

 ing 330 f.. July 19, 1906. 



Gaetanus si cumins resembles G. unicornis (Esterly, 1906, p. 

 57), rather closely, hut is easily distinguished by the much 

 greater length of the antennae and the character of the spines on 

 the basals of the fourth feet. 



Genus Undeuchaeta Giesbrecht. 

 Undeuchaeta bispinosa n. sp. 



PI. 26, fig. 4; pi. 29, figs. 4S, 56. 

 Adult female. This species resembles U. major Giesbrecht, 

 but the head is not crested (pi. 26, fig. 4), and the sides of the 

 last thoracic segments end in acute angles, nut in pointed pro- 

 cesses. The genital segment is of nearly the same shape as in V. 

 major, and has the hook-like appendage at the right of the ori- 

 fice, but in addition there is ;i spine on the right side of the seg- 

 ment about midway between the anterior and posterior borders 

 (pi. 29, fig. 56) ; there is a second and much shorter spine at the 

 left of tlie orifice. The segment carries a group of heavy spines 

 mi the left side at the posterior border, and usually the second 

 segment is similar in that regard. The anterior antennae are as 

 long as the cephalothorax, and the other appendages are not 

 noticeably different from those in U. major Giesbrecht. 



Length: Averages 4.5mm. 



Coloration: Opaque and without pigment in formalin. During life there 

 is a small amount of reddish pigment in the basals of the maxillipeds and 

 t.rt and in the anterior part of the intestine. 



Occurrence: Females are common in the deep hauls; for example, sta- 

 tion 1134, vertical from 285 f., June 26. 1906. 



