192 CEYLON PEARL OYSTER REPORT. 



length of genital segment 1 millim., length of abdomen 0-5 millim., length of egg- 

 sacs t*4 millims. 



There were two specimens of this species, both females, obtained from the gills of a 

 puffer, Tetrodon stellatus. They may be easily distinguished from other species of 

 the genus by the relatively large size of the carapace compared with the rest of the 

 body, by the correspondingly diminutive size of the fourth segment and the abdomen, 

 and by the rudimentary fourth legs, which are entirely concealed in both dorsal and 

 ventral view. The large rounded spine which projects between the rami of the third 

 legs is also peculiar to this species. 



Lepeophtheirus sesopus,* n. sp. Plate I., figs. 11 to 19. 



Female. Caraj)ace ovate, considerably narrowed anteriorly, and a little more than 

 two-fifths the entire length. Frontal plates prominent, but less than half the width 

 of the carapace. Eyes large and placed well forward. Thoracic area exceptionally 

 small, one-third the length and three-fifths the width of the carapace, its anterior 

 and lateral margins forming nearly a perfect half circle, its posterior margin slightly 

 re-entrant. Lateral lobes broad, blunt and short, leaving a wide sinus between 

 the carapace and the genital segment, which is entirely filled by the large basal 

 joints of the third and fourth pairs of swimming legs. 



The fourth or free thoracic segment is transversely elliptical and widened 

 considerably through the bases of the fourth legs. The genital segment is quadrate, 

 two -thirds the size of the carapace, and a little, wider anteriorly than posteriorly, 

 with evenly rounded corners. 



The abdomen is narrow, only one-sixth the width of the genital segment and less 

 than half its length. It is indistinctly three-jointed, the middle joint larger than the 

 other two, which are about the same size. The groove separating the terminal joints 

 is distinct and can be traced the entire width of the abdomen, but the basal groove 

 can be seen only at the margins, and it is not certain that the abdomen is really 

 jointed there. The anal lamina? are narrow, three times as long as wide and pointed 

 at the tips where each is armed with four small seta?. The egg-strings are wider 

 than the abdomen and three-quarters of the entire length ; the eggs are large, 

 50 or 60 in each string. 



Of the appendages, the second antennae have a large basal joint and a very slender 

 terminal claw, which is bent sharply at right angles near its tip. The basal joint is 

 re-enforced by a stout spine, pointing backward (fig. 12). 



The first maxilla? are small and well curved, the basal half fused to the ventral 

 surface of the carapace and only the tip free. As an offset to this, the second pair are 

 exceptionally large and stout, with a broad, triangular base and a long, straight, and 

 pointed tip which reaches far beyond the end of the mouth-tube. Each maxilla 



* vEsqnts, different footed, each pair of legs differing considerably from the ordinary type in this 

 genus. 



