224 CALIFORNIA ACADEMY OF SCIENCES. 



Genus Callomysis Holmes. 



Carapace with rounded angles and a deep posterior emargination. An- 

 tennal scale oblong, the outer margin naked and ending in a spine; inner 

 and distal margins ciliated. Distal portions of the thoracic legs divided 

 into miinerous articulations. Pleopods in the female rudimentary but 

 biramous; pleopods in the male short and small except the third pair, the 

 outer ramus of which is much elongated. Telson armed with lateral 

 spines and having a spiuous eniarginatiou at the tip. 



Type. C. maculata HOLMES. 



Callomysis maculata Holmes. 



Callomysis maculata HOLMES, Proc. Gal. Acad. Sci. (2), Vol. IV, 1895, p. 

 582, PI. XXI, figs. 37-44. 



Rostrum subtriangular. Last joint of the peduncle of the antennae 

 about as wide as long; acicle oblong, shorter than the peduncle, the tip 

 truncated. Maxillipeds (first thoracic appendages) with the exopod longer 

 than the endopod, the terminal portion divided into about fifteen articula- 

 tions; the following pair of appendages much like the preceding but with 

 a longer exopod; the endopods of the remaining pairs are longer than the 

 exopods and have the terminal portion divided into 10-13 articulations. 

 Pleopods rudimentary in the female, the rami of the first pair subequal; 

 in the following pairs the outer ramus is minute. In the male the inner 

 rami are shorter than the outer, the exopod of the third pair very long and 

 slender; fourth and fifth pairs subequal and a little shorter than the first 

 two pairs. Telson oblong, the sides armed with about eight strong spines; 

 apical emargination with several slender spines. Uropods subequal and 

 scarcely exceeding the telson. Nearly transparent, with large black pig- 

 ment spots having numerous, irregularly branching radiations. 



Length, 15 mm. 



Trinidad, Calif. ; taken on a sandy beach in which 

 the animals burrow as the waves recede. The females 

 taken in June had their marsupial pouches filled with 

 eggs or larvae. 



Genus Heteromysis Smith. 



Body comparatively short. Carapace emarginate behind, not covering 

 all the segments of the thorax. Eyes small. Antennal scale small, lamel- 

 liform, with both margins setose. Third maxillipeds much larger than 



