CRUSTACEA ISOPODA OF THE ' POECUPINE ' EXPEDITION. 235 



Gen. Akidognathia. 



Stebbing, Abstract P. Z. S. 1912, p. 42 (Nov. 5th). 



In near agreement with Gnathia, but oral membrane broadly produced, peduncle of 



second antennae elongate, mandibles narrow, first maxillgs developed, pleopods with 



fringes of setse, telsonic segment from short base narrowly produced to a sharp 



point. 



The name is compounded from the Greek a/ct?, liKl^o-i, a dart, and the name of the 

 companion genus. 



Akidognathia cbdipus. (PI. XXV.) 



Stebbing, Abstract P. Z. S. 1912, p. 42 (Nov. 5th). 



The single specimen, of the male sex, was in excellent preservation except for the 

 loss of the projecting part of the right mandible and the obscure condition at its 

 distant border of the delicate and much-advanced oral membrane. From this border 

 to the apex of the telsonic segment the length of the specimen was nearly four times 

 the greatest breadth, which is found at the fifth perseon segment. The second and 

 third perseon segments are sharply distinct ; the fourth has in the middle a longitudinal 

 line dividing it as it were into two sections and is clearly but not sharply distinguished 

 from the much larger fifth segment, which in turn is scarcely distinguishable from the 

 still longer sixth except at the sides ; the seventh segment is as usual very small and 

 limbless. The length of the narrow pleon does not exceed the width of the perseon ; 

 its segments are not sharply angled ; from the basal portion carrying the uropods the 

 telsonic segment at about a fifth of its length rather abruptly narrows, tapering to a 

 long drawn-out point, with setules on either side and a longer subapical pair. 



No eyes were perceptible. 



The first antennae have a robust first joint, once and a half as long as broad, the 

 second slightly shorter, with a strong distal spine, the third as long as the two preceding 

 joints combined, much curved, with many setae on the convex outer side ; the slender 

 flagelium nearly as long as the third joint of the peduncle, six-jointed, the second and 

 third joints the longest. 



The second antennae have the peduncle of unusual length, first joint very small, 

 second longer than the third, fourth nearly twice the length of these three combined, 

 very setose, fifth like the fourth but about three-quarters of its length ; the slender 

 palp shorter than the fifth joint of peduncle, eight-jointed, ^^ith the joints difficult to 

 distinguish. 



Mandibles with projecting part slender, a little curved, not reaching to the end of 

 the penultimate joint of the peduncle of the lower antenna.; underneath the base is 

 found a large inward-pointing tooth-like process, while underneath the broad projecting 



