V^OL. 3] Juday. — Ostracoda of the San Diego Region. 137 



not so strongly arched; anterior and posterior margins curving 

 over regularly into dorsal and ventral. Shell of most males and 

 females transparent; some with a brown color in the region of 

 the attachment of the valve muscles, others with almost the entire 

 shell tinged with brown. 



Length of female 0.57 ; male 0.5 mm. 



Catch 531, San Pedro, June 20, 1901. 



Genus Paracjrtheroma 



nov. gen. 



Shell in both male and female smooth, transparent, very thin 

 and weak ; with a small clasping process at the anterior and pos- 

 terior ends of hinge. Antennule short and strong, six-jointed; 

 the last four joints sometimes bent upward forming a knee with 

 the second joint ; the third, fourth, and fifth joints bear claw-like 

 setae; sixth joint long and slender, about five times as long as 

 wide; bearing three setae, one of which is claw-like, one elongated 

 and whip-like, while the third is a club-shaped sensory seta. An- 

 tenna rather short and strong, four-jointed; last jdint with two 

 long- claws. Masticating portion of mandible large and strong, 

 armed with a number of teeth ; mandibular palp four-jointed, the 

 respiratory plate of the first joint bears two long setae. Maxilla 

 of typical structure, with a long aberrant seta. First leg rather 

 short, third nuich elongated: the first joint of the first and second 

 legs with tv,'0 setae near the middle of the anterior margin and 

 one on the posterior margin ; on the first leg this joint has two 

 claws at the distal end, and on the second leg only one ; first joint 

 of thii'd leg with a minute spinule near the middle of the anterior 

 margin, a seta on the posterior margin, and a single claw at the 

 distal end. 



In the female the furca is represented by two small lobes, one 

 arising on either side of the posterior portion of the body a short 

 distance in front of the posterior margin; between the lobes are 

 two bifurcated setae which arise from the body wall near the 

 bases of the lobes. In the male the furcal-lobes are small, and 

 are closely luiited to the penis ; three small setae arise at the lower 

 margin of the lobes. The penis is distinctly separated into a large 

 basal portion and a triangular head portion. 



