262 CEYLON PEARL OYSTER REPORT. 



Second gnathopods (male) : very like S. marina, but the 3rd joint has the hind 

 margin crenate, with a setule in each notch. Hind margin of the hand straight and 

 densely hirsute; near the base of the dactylus a double-pointed tooth, the proximal 

 point the highest, the irregular distal one with 6 intra-marginal setules. Dactylus 

 as in S. marina (fig. 19. gn. 2 cJ). In the female the posterior margin of the hand is 

 convex, even, with the palm quite undefined, but 4 nearly equidistant spines and 

 some setse near the middle (fig. 19. gn. 2 ? ). 



First and 2nd peraeopods as in S. marina. 



Third perseopods: side-plate small, produced and rounded behind ; 1st joint oval, about 

 half as wide as long, longer than the next 2 ; 3rd joint but little produced behind ; 

 5th joint nearly as long as the 2 preceding ; dactylus strong (tig. 19. pp. 3 ). 



Fourth and 5th perseopods as in S. marina, hind margin of the 1st joint obscurely 

 crenate. 



First uropods reaching to the end of the 3rd ; peduncle longer than the rami ; rami 

 subequal, a spine in the middle of the inner and 2 or 3 spines in the middle of the 

 outer (fig. 19. ur. S ). 



S( cond uropods shorter than the 1st and 3rd. 



Third uropods : the peduncle longer than the 2 remaining joints, with 5 or spines 

 on the upper margin ; the last joint bent upwards in the middle and finely 

 denticulate on the upper margin (fig. 19. ur.). 



Telson concave above, oblong, with 4 spines increasing in size distally on the 

 proximal half of each side (fig. 19. ur.). 



Length of adult male, G millims. ; female, with ova, 5 millims. 



This species is undoubtedly very near S. valida, Dana, 1852, but the dentition of 

 the hind margin of the hand in the male is somewhat different in that species as 

 figured, and the same part in the female is described and figured as having " the palm 

 nearly straight and armed with a stout tooth towards the apex." From S. marina it 

 may be distinguished by the relatively short wrist of the 1st gnathopods and the 

 different dentition of the 2nd; the wider 1st joint of the 3rd perasopods ; the peculiar 

 structure of the last joint of the 3rd uropods, and the oblong truncate form and 

 armature of the telson. 



Perioculodes, G. O. Sars, 1894. 



Perioculodes serra,* n. sp. Plate IV., fig. 20. 



Kondatchi Paar and Cheval Paar, November, 1902. 



Head as long as the first 3 segments. Rostrum deflexed to the level of the 

 rounded ocular lobe and reaching the end of the 1st joint of the upper antennae. 

 First segment of the mesosome twice as long as the 2nd, which is the shortest. 

 Pleon segments obscurely carinate. 



* From the saw-like character of the 1st uropods. 



