320 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Mandibles with a tridentate cutting edge and a flattened somewhat twisted 

 lobe projecting inward from the lower side of the trunk and armed with 

 several spines on the rounded margin; on the lower side of the mandible 

 there is a large, flattened, lanceolate process, the entire inner margin of 

 which is closely set with spines; palp elongated, second joint about i^ times 

 the length of the first and setose on the distal % of the outer side; third joint 

 about I the length of the second, the outer margin slightly concave and 

 setose, the setae becoming longer towards the distal end which is furnished 

 with a few seta of larger size. First maxillae with the inner plate small and 

 armed with 3 ciliated spines, outer plate with the distal margin very oblique 

 and armed with 9 curved spine-teeth. Second maxillae with the movable 

 plates narrowly oblong and subequal; inner side of the basal plate nearly 

 straight and setose. Maxillipeds with the inner plate narrow and pointed, 

 about reaching the middle of the second joint of the large five-jointed palp 

 and furnished with several plumose seta, the inner margins armed with 

 hooks. 



Thoracic legs very spiny, the dactyls short with a short spine just behind 

 the tip. Uropods with the rami of equal length and reaching the tip of the 

 telson; end of the peduncle below the outer uropod with 3 or 4 spinules; 

 inner angle of the peduncle prolonged into a large, narrow, sharp process 

 reaching nearly to the rounded inner angle of the inner ramus; outer ramus 

 narrowly oblong, much narrower than the inner, and rounded at the tip and 

 armed with 4 or 5 spines among the setae on the distal portion of the inner 

 margin; inner ramus distally widened, the posterior angles rounded, the 

 terminal margin oblique, setose, and armed with short spines. 

 Length .63 inch. 



The ground color in the alcoholic specimens is a light 

 yellow and the presence of small dark-colored spots in 

 greater or less abundance gives rise to considerable varia- 

 tion in coloration. A constant mark in the specimens at 

 hand (but not equally plain in all) is a row on either side 

 of each thoracic segment of oblong light-colored spots lying 

 closely side by side. There is a space devoid of these 

 spots along the middle of the back between the upper ends 

 of the rows. 



Six of the eighteen specimens of Mr. Lockington may be 

 distinguished from the others by the presence of a pair of 

 minute tubercles on the upper side of the telson and the 

 more or less granulated margins of the posterior abdominal 

 segments. A careful comparison of the two groups of 

 specimens was made to determine whether there were any 

 other features by which they might be distinguished. It 

 was found that the six specimens in which there were tuber- 



