CALIFORNIA STALK-EYED CRUSTACEA. 229 



Genus Thysanoessa Brandt. 



Carapace rostrate, the antero-lateral angles produced. Eyes large, the 

 peduncles short. Antennules with the first joint flattened and devoid of 

 a dorsal, leaf-like appendage; flagella short. Maxillipeds slender and not 

 greatly elongated. First pair of legs much longer than the rest; merus 

 and carpus elongated; propodus compressed, the margins furnished with 

 strong setae; last joint very short and setose. Penultimate pair of legs 

 very small; endopod two-jointed. Last pair of legs quite rudimentary. 



Type. T. longipes BRANDT. 



Thysanoessa spinifera, sp. nov. 



Rostrum lanceolate from a triangular base, cat-mated above, the carina 

 extending back some distance upon the carapace. A prominent spine on 

 either side of the base of the rostrum. A small spine a very short dis- 

 tance above the acute antero-lateral angle of the carapace which is pro- 

 duced forwards; a sinus between this angle and the spines at the base of 

 the rostrum. Eyes large, nearly spherical, the cornea occupying most of 

 the surface. Anteunules stout, the first joint flattened, about reaching 

 the tip of the rostrum, the antero-external angle armed with a small spine; 

 second joiut prismatic, about two-thirds the length of the first but a little 

 longer than the third. Antennae scarcely half the leugth of the body, the 

 last joint of the peduncle about three-fourths the length of the third, and 

 reaching nearly to the tip of the acicle; acicle narrowly oblong, the sides 

 nearly parallel, the tip reaching the tip of the second basal joint of the 

 antennules; outer margin slightly concave, ending distally in a spine; 

 inner margin slightly convex and furnished with long setae; the distal end 

 is broadly rounded, transverse, and furnished with setae like the inner 

 margin. Mandibles stout; terminal joint of the palp oblong-elliptical, 

 the inner margin setose, the setae increasing in length towards the tip, 

 the terminal seta long and stout. Maxillipeds moderately long; first joint 

 of the endopod short and tapering distally; second joint elongated, slen- 

 der, about as long as the following joints combined; third joint longer 

 than the fourth; last joint tapering, about three-fifths the length of the 

 preceding one, the tip bearing a very long seta. First pair of legs (gnath- 

 opods) comparatively short for the gemas, exopod two-jointed, the first 

 joint not reaching the tip of the first joint of the endopod; second joint 

 of the endopod slender and elongated, furnished with fine cilia on one 

 margin; third joint furnished distally with long setae and about as long 

 as the two following joints combined; fourth joint with both margins fur- 

 nished with strong setae; terminal joint very short, furnished with four 

 or five large setae and several smaller ones. Second pair of legs with the 



