BORRADAILE— ON THE PONTONIIN^ 353 



carapace, two, large, standing on a crest over the orbit, two to four, small, near 

 antennule, three isolated near the tip, most of ventral teeth large and set on a crest 

 between the antennules ; antennal and hepatic spines present, the latter nearly in 

 the branchiostegal position ; antennular stalk three-quarters of length of antennal 

 scale, its basal joint not much expanded, with stylocerite and distal spine small, the 

 second joint shorter than the' third, the second and third joints together shorter than 

 the first ; basipodite of antenna with very small spine, scale not half length of rostrum, 

 slightly outcurved, its sides converging slightly towards the end, which is subtruncate, 

 its subterminal spine not reaching the end, stalk of antenna more than half the length 

 of first joint of antennule ; third maxilliped reaching or outreaching end of second joint 

 of antennule ; first leg outreaching antennal scale by fingers, its wrist and palm 

 subequal, fingers a little longer, its arm equal to wrist and palm together ; second legs 

 equal and similar, outreaching antennal scale by hand and part of wrist, fingers rather 

 longer than palm, wrist more than half length of palm, arm equal to wrist and palm 

 together, all joints unarmed ; walking legs long, slender, with spines under the propodite, 

 the longest at the end, dactylopodites long, nearly straight, simple ; telson longer than 

 sixth abdominal segment, shorter than uropods. 



Length of longest specimen, 40 mm. 



Maldive Is. 



Genus Urocaris Stimpson, 1860. 



Proc. Ac. Philadelphia, 1860, p. 89. Kingsley, lb., 1879, p. 383 (1880). Rathbun, 

 Bull. U. S. Fish Comm. xx. ii. p. 126 (1901). 



Definition : Body slender, much compressed ; sixth abdominal segment elongate ; 

 rostrum with a toothed crest above but toothless below ; outer flagellum of antennule 

 deeply cleft ; antennal scale long, narrow ; mandible without palp ; second maxilliped 

 without gill ; third maxilliped slender, with arthrobranch ; legs very slender, their 

 dactylopodites little curved. 



Key to the species of Urocaris : 



I. Bostrum very long and slender and much upcurved. 



U. psamathe de Man, 1902. 



II. Bostrum of moderate length, never very slender, hardly if at all upcurved. 



A, Bostrum has high, arched dorsal ci'est. 



U. infraspinis Bathbun, 1902. 



B. Bostrum has low dorsal crest. 



1. Bostrum arched, with concavity below. Third abdominal segment projects 

 behind. 



a. Two teeth of dorsal crest stand behind orbit. Walking legs biunguiculate. 

 U. longicaudata Stimpson, 1860. 

 SECOND SERIES— ZOOLOGY, VOL. XVIL 45 



