18 CEYLON PEARL OYSTER REPORT. 



carrying a shorf booth or spine at the inner angle, and a longer one inserted a little 

 behind and outside the other. 



The mandibles are elongate, that on the left bidentate, that on the right with the 

 cutting edge undivided ; each has a narrow, transparent, apparently very feeble blade 

 representing the molar, but devoid of the saw-teeth which are conspicuous in 

 Eurydice and Oirolana. The palp is implanted near the base of the trunk, its 

 second joint much longer either than the first or falciform third. 



The maxillipeds are narrow, the three terminal joints setose, none very widely 

 expanded. 



The first gnathopods are moderately robust, with four short stout spines conspicuous 

 on the stout fourth joint ; the fifth joint short, not produced along the inner side of 

 the sixth joint, which is very slightly armed : the finger curved, simple. The second 

 gnathopods and first peneopods agree with the preceding limb. The four following- 

 pairs have a different character, with less tendency to geniculation, except between 

 the second and third joints. There is little difference in length between the joints 

 from the second to the sixth, the first three of these having the expanded distal 

 margin beset with spines of varying length, and some of the spines, especially on the 

 hinder apex of the fifth joint, are serrate. The finger shows a little projection at the 

 base of the nail. 



The pleopods have large rami. In the second pair the male appendix, affixed close 

 to the base of the ramus, reaches a little beyond it, and is abruptly narrowed to a 

 short linear apex ; near the base its margin is fringed with minute setules. 



The uropods have the peduncle considerably produced, spinose on its outer part, 

 but dorsally almost clear, the long process having lateral and apical armature. The 

 rami are strongly fringed like the telson, and the broad inner ramus, which reaches 

 a little beyond the telson, is dorsally sprinkled with short spines, but the much 

 narrower outer ramus has much of its dorsal surface smooth, evidently to suit its 

 habit of folding underneath its companion. 



The smooth ventral surface is orange-coloured, the spiny coating of the back dark 

 brown, the limbs quite pale. 



Length of the specimen in slightly bent position, It) millims. , which is about two and 

 a-third times the breadth. A second specimen measured 12 millims. in length by 

 6 millims. in breadth. 



Locality : The smaller specimen was from coral reefs, Gulf of Manaar, the larger 

 from Station XXXIX., south of Galle, up to 30 fathoms. 



The clothing of this species gives it, when under the microscope, a very striking- 

 appearance ; especially its caudal fan, by the grouping and variety of the spines and 

 the addition of the long feathered setre in more or less symmetrical arrangement, 

 produces a particularly agreeable effect on the eye. I have named it in honour of 

 my friend the Rev. A. M. Nokman, h.t'.L., F.R.S., whose services to the zoology of 

 invertebrates are justly celebrated. 



