286 CEYLON PEARL OYSTER REPORT. 



Photis, Kroyer, 1842. 

 Photis longicaudata (Sp. Bate). Plate VI., figs. 43. 



Wist ( 'oast of Ceylon, from Galle northwards; generally abundant. 



Length of female with ova, 3'5 millims. 



I have referred the specimens examined to the above species chiefly on account of 

 the prominence of the ocular lobe (fig. 43. a). In other respects it is equally near the 

 other two species described hy G. O. Sabs, the limbs in some specimens being as 

 robust and hairy as in P. reinhardi, Kr., while the hand of the 2nd gnathopods 

 resembles that of P. tenuicornis (fig. 43. gn. 2 ). It is a question whether these 3 species 

 and P. poller, A. 0. Walker, ought not to be merged in the oldest recorded form, 

 P. reinhardi. The Ceylon specimens are remarkably variable. The colour in spirit 

 is dark yellowish-green spotted with black or brown. 



One of the forms has the hind margin of the outer ramus of the last 2 pairs of 

 pleopods expanded near the base and furnished with peculiar longitudinally-striated, 

 tapering plumose setae radiating symmetrically from the curved margin (fig. 43. pip.). 

 In this form the side-plates and gnathopods are setose. 



Photis longimanus, n. sp. Plate VII. , figs. 44. 



From pearl oysters, East Cheval Paar, 8th November, 1902 ; 5 specimens. 



Male. Head about as long as the first two segments. 



Ocular lobe reaching almost to the end of the 1st joint of the lower antenna?. Eye 

 large, occupying almost the whole lobe, dark. 



Hind angle of the 3rd pleon segment rounded. 



Upper and lower antennae subequal, scarcely reaching to the pleon, sparsely setose ; 

 1st joint of the upper twice as thick as, but shorter than, the 2nd, and subequal to the 

 3rd ; flagellum 6-jointed, subequal to the 2nd and 3rd joints of the peduncle together. 



First joint of the lower antennas about half as long as the second, which is sub- 

 equal to the 3rd ; flagellum 6-jointed, rather shorter than the last 2 joints of the 

 peduncle. 



Mouth organs and maxillipeds normal. 



First gnathopods : side-plates oblong, much wider than deep, angles rounded ; 1st 

 joint as long as the 3rd and 4th and at least as wide as the hand ; wrist as wide as, and 

 considerably longer than, the hand, which is oval ; the palm undefined (fig. 44. gn. 1 ). 



Second gnathopods : side-plates small, rounded-oblong ; the first 4 joints very 

 short and stout. Wrist brought round the base of the hand on the outside and 

 produced beyond it in an oval lobe. Hand long, narrowing distally, a strong blunt 

 tooth near the base on the inner surface, the hind margin divided into 3 nearly equal 

 concave spaces by this and 2 other teeth, the middle one being the smallest. Dactylus 

 strong, reaching the basal tooth (fig. 44. gn. 2 <$). 



The perseopods do not differ materially from those of P. reinhardi, Kr., except in 

 being less setose ; the last pair extends to the end of the 3rd uropods. 



