HYPERIIDAE 279 



portions of segments 1-3 each with an oblique keel which forms the lower margin of the 

 posterior half of each pleuron ; segment 4 (in dorsal view) wider than long ; segments 5 

 and 6 completely fused, with a notch on lateral margin. Telson longer than wide, ex- 

 tending to three-quarters of peduncle of uropod 3, ovate-lanceolate, tapering rather 

 rapidly to the acute apex. 



Antenna 1, flagellum very large, thin, laminate, apex acute and upturned, lower 

 margin arcuate and very minutely serrulate, inner surface with a band of dense, very 

 fine setae. Antenna 2, flagellum ensiform, upper margin with numerous fascicles of 

 setae. 



Epistome gibbous. Upper lip bilobed (somewhat asymmetrically). Mandible, 

 cutting edge with rounded denticles, and ending in a tooth at posterior corner ; secondary 

 cutting plate in left mandible only, subcircular , also with rounded denticles ; the " molar 

 projection thin, laminate, its margin with spinules and setae; palp with 3rd joint sub- 



Fig. 164. Pegohyperia princeps, Brnrd. a, b. Peraeopods 3 and 5. 

 c. Uropods 2, 3 and telson. 



equal to 2nd, all the joints smooth. Maxilla 1, inner lobe wanting, outer lobe strong, 

 twisted, its distal margin with two strong teeth, then a small one, then a moderately 

 large one, followed by two small ones, setae arranged as in figure, palp large, laminate, 

 curved, ovate, its distal margin minutely denticulate. Maxilla 2, inner lobe with a single 

 apical spine, and a subapical dense whorl of setae, outer lobe with three strong apical 

 spines, and some setae on inner and outer margins. Maxilliped, inner plates completely 

 fused into a conical projection tipped with two spinules, and a subapical patch of setae; 

 outer plates ovate, inner margin minutely serrulate. 



Gnathopod 1, 5th joint triangularly expanded, laminate, apex reaching three-quarters 

 along 6th joint, upper and lower margins finely pectinate, 6th narrow ovate, lower 

 margin pectinate, a low longitudinal ridge on outer surface. Gnathopod 2 similar to 

 gnathopod 1, but more slender, the produced apex of 5th joint reaching to end of 6th. 



Peraeopods 1 and 2 similar to one another, but the 2nd joint in the 2nd not so markedly 

 flask-shaped as in the 1st, 4th and 5th joints subequal, 6th longer, lower margins of 5th 

 and 6th minutely pectinate. Peraeopods 3 and 4 a little longer than peraeopods 1 and 2, 



