1913] Uanscn: Oil Soiiir Califoniinii Scliizopocla 175 



II. jMysidacea 



1. Siriella paciflca Holmes 

 P!. 9, figs. ]«•/ 



In the report on the "Siboga" Sehizopoda I (1910) enum- 

 erated twenty species of this genus, eleven of which were estab- 

 lished as new to science, and some hitherto overlooked or not 

 sufficiently valued characters were pointed out. As to Siriella 

 pacifica Holmes, I stated that it "ought to be re-examined," 

 because it probably belongs "to a group of the genus, whose 

 forms must be established on fidl-grown males, as the females in 

 two or three cases cannot be sejjarated with certainty, while the 

 males show excellent specific characters in the fourth pair of 

 pleopods. ' ' 



Having now examined two specimens determined by Holmes, 

 viz.. an adult male and a female, my supposition as to the affinities 

 of »S'. pacifica prove to be correct. The species is on the whole 

 more nearly related to *S'. iiioniata H. J. H. and S. media H. J. H. 

 than to any other form. 



Description. — Moderately robust. Carapace in both sexes 

 somewhat produced, the frontal plate (pi. 9, figs, la, If) being 

 a broad, rather low triangle with the vertex somewhat produced, 

 acinninate and acute. Eyes in the male (fig. la) considerably 

 smaller than in allied forms, seen from above conspicuovisly 

 shorter and narrower than the last joint of the peduncle, the 

 posterior margin of which is rather convex ; eyes in the female 

 distinctly larger than in the male, seen from above (fig. 1/) con- 

 spicuously shorter but slightly broader than the peduncular joint. 

 Antenmile in the male with third peduncular joint only a little 

 longer than broad ; flagellum in the male extremely long, reaching 

 beyond the hind margin of fourth abdominal segment. Antennal 

 squama subequal in both sexes, with the terminal lobe much 

 broader than long (fig. la). 



Pseudobranchial rami on second to fourth pairs of male pleo- 

 pods somewhat circularly curved, less spirally twisted than in 

 S. inornata. Both rami of third pair of male pleopods terminating 

 in a robust, spiniform, nearly straight, seemingly naked seta not 

 longer than the normal setae on the preceding joint and with the 



