268 CEYLON PEARL OYSTEE REPORT. 



Third perseopods : side-plates broad ; 1st joint expanded before and behind, as wide 

 as the side-plate, the front margin setose; 3rd joint longer and twice as wide as the 

 ttli : Mli about as long as the 3rd (fig. 26. pp. 3 ). 



Fourth perseopods like the 3rd. 



Fifth perseopods: side-plates much smaller than the 1st joint, which is much 

 expanded behind, straight in front ; 3rd joint widening somewhat distally and 

 produced at the posterior angle; 4th shorter and narrower than the 3rd, oblong, 

 narrowing distally; both these joints densely setose and spinous on the front and 

 sparsely on the hind margin ; 5th joint as long as the 4th, very slender, naked. 

 Dactylus small, in a straight line with the 5th joint. The seta? on the 3rd and 4th 

 joints are simple, i.e., not plumose (fig. 26. pp. B ). 



First uropods extending beyond the 2nd and these beyond tin' 3rd : rami of the 

 1st hardly as long as the peduncle; inner ramus of the 2nd shorter than the outer; 

 rami of the 3rd pair wider than the others, about twice as long as the peduncle, 

 without seta? or spines. 



Telson divided almost to the base with a setule at the tip of each division. 



Length of female with ova 2 millims. 



The most conspicuous difference between this species and G. coalita is tin' 

 smoothness of the dorsal surface of the urns, but there are also differences in the 

 form and armature of the limbs. Both Norman and Della Valle have described 

 male specimens; besides the shorter lower antenna' and absence of plumose seta' on 

 the 3rd uropods, there is a curious difference in the relative proportions of the 

 mesosome segments in the 2 sexes of both species. 



Hornellia,* n. gen. 



Body rather tumid. Segments of pleon and urns with postero-dorsal teeth. 



Head not rostrate or vaulted in front. Eyes distinct, not coalescent. 



Upper antenme with an appendage ; flagellum slender, much longer than the 

 peduncle. 



Mandibles with well-developed molar tubercle, spine-row, and toothed cutting 

 edges; palp long, 3-jointed, 2nd and 3rd joints subequal (tig. 27. m.). 



First maxillae with the 2nd joint of the palp widened towards the obliquely truncate 

 end. which is crowned with spine-teeth and seta; alternately (tig. 27. ml 1 ). 



Maxillipeds well developed in all parts ; 4th joint of palp dactylifbrm (fig. 27. mxp.). 



GnathopOds subequal and similar, like those in Halimedon. 



Third uropods of moderate length, with subequal rami. 



Telson long and deeply cleft, 



This genus will probably find a place in the as vet undefined family Melphidippidse, 



STIMUilNO. 



* See footnote, p. 258. 



