284 CEYLON PEARL OYSTER REPORT. 



Cheiriphotis megacheles (Giles). Plate VI., figs. 42. 



Melita megacheles, Giles (male), ' Journ. Asiatic Soc. Bengal,' 1885, vol. liv., p. 70, pi. iii. 

 Eurystheus hirsutus, Giles (female), 'Journ. Asiatic Soc. Bengal,' 1887, vol. lv., p. 227, pi. viii 



Rather abundant along the West Coast from Colombo northwards. 



Third pleon segment rounded behind ; lower margin straight, hind margin convex. 



Head not quite as long as the first 2 segments, of which the 1st is the shorter ; 

 ocular lobe moderately produced, angular, the angle obtuse and apiculate (fig. 42. o.l.). 



Upper antennas : peduncle subeqnal to that of the lower ; 1st joint shorter and 

 wiiler than the 2nd, longer than the 3rd ; flagellum rather variable in length, 

 generally subequal to the last 2 joints of the peduncle, about 13-jointed. Appendage 

 (in female) reaching the end of the 4th joint of the flagellum, 4-jointed, the first 

 2 joints together subequal to the 4th. In the males the appendage- is 3-jointed, the 

 1st joint shorter than the 2nd, the 2nd and 3rd subequal ; the whole reaching to the 

 end of the 2nd joint of the flagellum ; the appendage has, in addition, a minute 

 terminal joint in both sexes. 



Lower antennas rather stronger than the upper, the 1st joint about one-third of the 

 2nd ; 2nd, 3rd, and flagellum subequal, the last 9-jointed. Both pairs of antennae 

 are rather thinly clothed on the under side with long setae. 



Mouth organs as in Gammaropsis, except the inner plate of the 1st maxillae, which 

 is round-oval, with 4 setules on one side. 



Maxillipeds as in Gammaropsis. 



First gnathopods : sideqjlates acutely produced in front and fringed round the 

 blunt point and below with long setae, especially in the female. The 1st joint is as 

 long as the wrist, which is longer than the hand and has the hind margin rather 

 flattened and very setose ; the hind margin of the hand is evenly convex, with no 

 definite palm, and is setose on the middle part. Dactylus about half as long as the 

 hind margin, with a row of setules on the inner margin (fig. 42. gn. 1 ). 



Second gnathopods (female) : Sideqjlates small subquadrate, angles rounded, 

 lower margin fringed with long setae. First joint very strong, subequal to the hand, 

 with long setae on the front margin ; wrist half as long as the hand, triangular, 

 produced and setose behind ; hand subovate, palm oblique, uneven, defined by a strong 

 tooth just below the point of the dactylus (fig. 42. gn. 3 ? ). 



The young male has the hand much wider than the female, though less so than the 

 adult male ; the palm is somewhat obliquely transverse, defined by a strong pointed 

 tooth ; near the middle is a double pointed tooth and a single one near the base of the 

 dactylus ; the latter is wider in the middle than in the adults. The wrist is produced 

 towards the front margin of the hand and cannot be seen behind (fig. 42. gn. 3 S jr.). 



In the adult male the 1st joint is shorter, the width being three-fourths of the 

 length, which is subequal to the next 2 joints. The wrist has disappeared or can 

 only be seen in a reduced form through the wall of the 3rd joint. The hand is 



