Vol. 3] Judaij. — Ostracoda of the San Diego Region. 145 



Length 1.45 ; height 0.8 mm. 



Distribution. — Adriatic (Grube) ; Spezzia, Messina, Goletta, 

 S.yracuse, coast of Norway (Sars) ; Bay of Biscay (Marquis de 

 Folin) ; coast of England and Ireland, and Sicily Islands (Brady, 

 Norman, and Robertson) ; Gulf of Naples (G. W. Miiller) ; coast 

 of southern California, catch 571, Ballast Pt., San Diego Bay, 

 July 26, 1901, surface; catch 589, San Pedro, August 1, 1902; 

 catch 644, San Diego Bay, July 7, 1903. 



Genus Pleoschisma Brady. 1890. 



Shell dense, surface smooth, pitted, or tuberculated ; antennal 

 sinus more or less distinct. Eyes rather small. Antennules in 

 both sexes similar to those of Philomedes. In the male the sec- 

 ondary branch of the antenna is three-jointed, the third reflexed 

 upon the second forming a grasping organ ; in the female this 

 branch is simple, one-jointed. Mandible with four or five joints; 

 in the female the first joint bears a bifid masticating process, male 

 without niasticating process. The first maxilla consists of a two- 

 jointed principal lobe and four smaller lobes, all bear setae; at- 

 tached to the lobes is a large respiratory plate bearing plumose 

 setae on its margin. Vermiform limb with a single claw-like 

 process at its apex. Furea short and broad ; armed with both 

 setae and claws. 



Pleoschisma oblonga nov. sp. 



PI. 19, fig. 12; pi. 20, figs. 1-7. 



Shell of male in side view, oblong-ovate, truncate behind; 

 about one aud a half times as long as high; ventral margin 

 broadly arched, passing over gradually into the anterior and pos- 

 terior margins; dorsal margin rather strongly arched anteriorly 

 but rounding off regularly into the posterior margin; rostrum 

 broad, antennal sinus distinct but shallow and wide ; a few short 

 setae along margins of valves; transparent margin rather wide 

 and densely ciliated. The surface of the shell is reticulated ; these 

 reticulations vary in size and shape, anteriorly they are arranged 

 in rows and present the appearance of overlapping scales ; in some 

 instances, the individual areas composing the rows are not dis- 



