DESCRIPTION OF A NEW SCHIZOPOD FROM LAKE 



MERCED. 



BY SAMUEL J. HOLMES. 



[With Plate xix.] 



Neomysis mercedis sp. n. 



Rostrum rounded. Eyes normal. Outer flagellum of 

 first antennae much longer than the inner one; sensory 

 organ of the male well developed. Antennal scale narrow, 

 elongate, tapering gradually to an acute tip, and furnished 

 with thickly set plumose setae on both margins. Mandibles 

 with three short plumose setae between the cutting edge 

 and molar tubercle; palp large; first joint very small; 

 second joint large and wide, tapering from near the 

 middle to the distal end; third joint narrower and some- 

 what shorter than the second, the sides parallel up to a 

 short distance from the tip, which is furnished with a large, 

 incurved seta. The distal portion of the exopod of the 

 maxillipeds is divided into eight articulations. The 

 endopod of the following pair of appendages is longer 

 than that of the maxillipeds ; the terminal joint is oblong, 

 entire, and bears a large, terminal, claw-like seta; distal 

 portion of the endopod divided into nine joints. The 

 endopods of the succeeding appendages are larger and 

 more slender than those of the former pair, and the 

 terminal segment is long, narrow, incurved, and divided 

 into 8-10 setiferous articulations, the terminal one of 

 which is furnished with a claw. In the male all the pleo- 

 pods, except the fourth pair, are simple' and rudimentary, 

 as in the female, but each bears a small, stump-like pro- 

 cess on the inner side, near the base, which may repre- 

 sent the rudiment of an endopod. In the fourth pleopod 

 of the male the endopod reaches about the middle of the 

 slender, elongated exopod; the terminal joint of the 

 exopod is short, and bears two large, sparingly plumose 

 setae at the tip. Telson shorter than the inner ramus of 

 the uropods, but about equaling the length of the preced- 



Proc. Cal. Acad. Sci., 2d Ser.. Vol. VI. June 24, 1896. 



