254 CEYLON PEARL OYSTER REPORT. 



Fifth peneopods : posterior lobe of the 1st joint reaching to the end of the 2nd, the 

 anterior half of the lower margin fringed with long plumose seta' : 2nd and 3rd joints 

 short, their angles hardly produced ; anterior angle of the 4th joint produces! one- 

 third of the length of the 5th, spinous on the truncate end ; 5th joint wide oval, 

 truncate at the end: 6th as long as the 5th, tapering gradually to a long curved, 

 very sharp point (tig. 14. pp. 5 ). 



First uropods reaching to the middle of the rami of the 2nd ; rami smooth, curved, 

 subequal, considerably Longer than the peduncle; 2nd pair longer than the 1st, 

 peduncle longer than rami, which are subequal, straight and spinous, the spines 

 slender and, at the distal end of both, very long (tig. 14. up. 2 ). 



Third uropods: peduncle shorter than the rami in the proportion of 3 : 5, unarmed 

 except 3 slender spines on the inner side ; outer ramus a little longer than the inner, 

 outer margin, with 4 small spines and plumose seta?, prolonged to a point beyond the 

 inner, which is furnished with long plumose marginal setse <>n the distal half; this 

 ramus is narrow near the base and widest near the middle : the inner ramus is widest 

 about one-third of the distance from its base and is naked except 2 or 3 slender spines 

 near the rounded point and 3 slender spines and 2 plumose seta? on the tip (up. 3 ). 



The telson is convex on the upper side, cleft rather more than half its length, the 

 sides of the cleft contiguous almost the whole length : margins of the divisions 

 parallel, the ends l'ounded with a terminal notch and 2 slender spines (tig. 14. t.). 



The peculiar shape of the head and appearance of the eye distinguishes this species 

 at once. In the form of the mandibular palp it differs from G. 0. Sars' definition, 

 but as one or two of Mr. Stebbing's " Challenger" species differ -in the same way, it 

 would seem advisable to disregard that part of the definition. 



Ainpelisca chevreuxi,* n. sp. Plate III., figs. 15. 



Station LIII. One specimen. Length, 7 millims. 



Head narrow and rounded in front, longer than the first 2 segments. Eyes large 

 and prominent, one at the extreme end of the head, the other below the base of the 

 upper antenna?. 



Third pleon segment: the hind and lower margins rather convex, the posterior 

 angle a little produced, obtuse (fig. 15. pi. 3 ). 



Urus with a shallow carina on the 1st segment. 



Upper antennee reaching to about one-third of the last joint of the peduncle of the 

 lower; 1st joint more than half as long as 2nd. 3rd shorter than the 1st joint of the 

 llagelhnn. which is about 8-jointed. 



Lower antenna' scarcely half the length of the body, the 3rd joint rather longer 

 than the 2nd. 



Gnathopods and 1st and 2nd perasopods of the usual form : dactylus of the latter 

 rather longer than the 2 preceding joints. 



* Named after that distinguished Amphipodist, Monsieur E. Chevkeux. 



