298 CEYLON PEARL OYSTER REPORT. 



Upper antennae : the 1st joint half as long' and twice as wide as the 2nd, which is 

 equal to the 3rd ; flagellum subequal to the 3rd joint, 3-4-jointed, the 1st as long as 

 or longer than the remainder ; appendage about half as long as the 1st joint of the 

 flagellnni, 1-jointed (fig. 53. ant. 1 ). 



Lower antennas : the 1st joint sub-globose, more than twice as wide as the 2nd, 

 winch is considerably shorter than the 3rd and subequal to the flagellum; this is 

 3-4-jointed. 



First gnathopods : side-plates much produced in an acute angle, with a seta at 

 the tip ; the rest of the limb much like the last species (fig. 53. gn. 1 J). 



Second gnathopods of female : side-plates small, subquadrate, with rounded angles. 

 First joint rather shorter than the hand ; 3rd more than twice as long as the 2nd, 

 and produced beyond the wrist as in the last species ; wrist small and triangular ; hand 

 wide-oval, both margins convex, especially the front, and setose ; palm hardly defined, 

 but a spine within the point of the dactylus, which is slender ; the setae are stiff and 

 spine-like. Incubatory lamellae very large, sub-oblong, the upper part spotted with 

 red (fig. 53. gn.- 2 ). 



Second gnathopods of male : 1st joint expanded distally, longer than the next 3, 

 with a channel in front to receive the hand ; 3rd joint twice as long as the 2nd, the 

 hind margin rectangular ; the wrist very small and almost concealed by the 3rd joint ; 

 hand much longer than all the preceding joints united, oval, a strong tooth near the 

 middle of the hind margin defining the palm, between which and the base of the 

 dactylus are two tubercles with concave interspaces, the whole clothed with unequal 

 plumose setae. Dactylus barely reaching the palmar tooth, with a row of denticles on 

 the inner margin. The sculpturing of the palm is somewhat variable (fig. 53. gn. 3 S). 



First and 2nd peraeopods : the 1st joint subequal to the 4th joint, with a laminar 

 expansion of the front margin which is rounded and furnished with a group of stiff' 

 setae ; 3rd joint shorter than the 4th, produced and spinous in front ; 5th joint almost 

 as long as the 3rd and 4th united (fig. 53. pp. 1 ). 



Third peraeopods : 1st joint shorter than the 4th, with a semicircular membranous 

 expansion behind (fig. 53. pp. 3 ) ; the rest as in the preceding pairs. 



Fourth and 5th peraeopods : 1st joint wider above, but otherwise like the 3rd pair : 

 the 5th pair reaches far beyond the ends of the uropods (fig. 53. pp. ). 



First uropods : peduncle subequal to the outer ramus, reaching beyond the telson ; 

 inner ramus about one-fourth longer and wider (fig. 53. ur. ). 



Second uropods shorter in extent than the 1st ; peduncle reaching to the end of 

 the telson, shorter than the outer ramus, which is one-third shorter than the inner. 

 In both pairs the rami are spinous, the terminal spines about one-fourth of their lenyth. 



Third uropods not reaching beyond the end of the telson. 



The telson has the form of a truncated cone, the apex directed backwards, with a 

 long terminal and 2 shorter subterminal spines (fig. 53. t.). 



Length of male, 4 inillims. ; of female, with ova, 2"5 millims. 



