60 CEYLON PEARL OYSTER REPORT. 



PLATE III. 



A. Argalhona narmani, n. gen. et sp. n.s., lines indicating natural size of the specimen represented by tho 



adjoining figures in dorsal and lateral views ; PL, pleon in dorsal view, more highly magnified ; 

 a.s., a.L, the first and second antennae ; l.s., the upper lip, with the epistome surmounted by the 

 frontal lamina; /.?'., the lower lip; m., in., the left mandible entire, and part of the right mandible ; 

 nt.r. 1, mx. 2, mxp., the first and second maxillae and the maxillipeds ; (in. 1, gn. 2, prp. 5, the first 

 gnathopod without side-plate, the second gnathopod and fifth perreopod each with its side-plate ; 

 pip. 2, the second pleopod. 



The mouth parts are magnified on a higher scale than the other appendages, but the uropods 

 figured in attachment to the pleon are enlarged on a lower scale than the rest. 



B. Cilicrca latreillii, Leach, juv. n.s., lines indicating natural size of specimen figured below in dorsal and 



dorso-lateral aspects; PL, pleon in dorsal view; a.s., a.L, first and second antenn;e ; l.s., upper lip 

 with epistome; map., maxillipeds; gn. 1, first gnathopod. 



The mouth parts are more highly magnified than the other appendages. 



C. Janira (1) nana, n. sp. n.s., line indicating natural size of the specimen ; PL, pleon, without appendages ; 



a.s., a.L, first antenna and four basal joints of second; l.s., Li., upper and lower lips; m., in., mx. 1, 

 mx. 2, mxp., the mandibles, first and second maxilla?, and a maxilliped ; gn. 1, gn. 2, pip. 1, first and 

 second gnathopods and first persaopod, the finger of the first gnathopod and that of the first 

 perseopod more enlarged; pip. 1, pip. 2, the first and (one of the) second pleopods, the two pairs 

 together forming the male operculum. 



The mouth parts are more highly magnified than the other appendages, being on the same scale 

 as the more enlarged finger of the first gnathopod. 



PLATE IV. 



JEga omtmatophylax, n. sp., . n.s., lines indicating natural size of the specimen figured in dorsal aspect ; 

 ft, the head in dorsal aspect; C.L., lateral view of the head in conjunction with the first two 

 segments of the peraaon ; Per.s. 1., anterior part of first segment of perason in dorsal view; 

 g.p., ventral plate of the seventh perreon segment, with the genital papillae also more highly 

 magnified ; PL, Pleon in ventral view, after removal of the pleopods ; a.s., a.L, first and second 

 antennas ; m., mx. 1, mx. 2, mx. 2, mxp., mandible, first maxilla, second maxilla in two positions, 

 maxillipeds in ventral aspect. These organs are magnified on a higher scale than the other details 

 in general, and the distal parts of mandible, first maxilla, and maxillipeds are again more highly 

 magnified. In the mandible the third joint of the pjalp is missing. The further enlargement of 

 the maxillipeds is from the dorsal aspect, gn. 1, gn. 2, gn. 2, prp. 3, prp. 5, pip. 1, 2, 5, urp., the 

 first and second gnathopods, third and fifth perseopods, first, second and fifth pleopods, and the 

 uropod. The portions of these appendages which required further enlargement are on the same 

 scale as the principal figures of the mouth organs. Both members of the second pair of gnathopods 

 are figured, to show the difference mentioned in the text. 



PLATE V. 



A. dEga ommalophylax, n. sp., $ (*!). n.s., lines indicating natural size of specimen figured above in dorsal 

 view ; C, ventral view of the head ; l.s., upper lip surmounted by the epistome and frontal lamina ; 

 m., m., the two mandibles, with higher magnification of a seta from second joint of palp, and of 



