164 CEYLON PEAEL OYSTER REPORT. 



of Sars) the oval chitinous plate, which forms a valve-like lid to the respiratory 

 aperture, is well defined. 



The second maxillipeds (fig. 15) have the basis sub-equal in length to the remaining 

 segments together. The ischium, which is not distinct in most species of Cyclaspis, 

 is here well defined though small. 



The third maxillipeds (figs. 16, 16a) are expanded, and are opercular in function, 

 serving along with the basal segments of the first legs to completely cover in the 

 other mouth parts. The basis is in the natural position of the parts partly covered 

 by the basis of the first leg, and its distal part, which is exposed, is more strongly 

 calcified and sharply defined from the concealed proximal part. At its distal end the 

 segment is produced into a long and narrow curved process reaching nearly to the end 

 of the merus. The ischium, unlike that of Cyclaspis. is very broad, not narrower 

 than the succeeding segment. The three distal segments are comparatively slender. 



The first legs (fig. 21) are long, extending beyond the pseudorostrum by nearly 

 the length of the last two segments. The basis is very broad and flattened, narrowing 

 suddenly at about its distal third and produced beyond and (in the natural position) 

 above the articulation of the next segment into a sharply pointed process which 

 extends beyond the distal end of the ischium. The rest of the limb is slender, and 

 the last three segments are much elongated, the carpus and the propodus sub-equal 

 and a little longer than the dactylus. 



The second legs (fig. 17) are much shorter than the succeeding pairs and have a 

 peculiar form. The basis is about equal to the remaining segments together. The 

 ischium is suppressed. The merus is very short, but is produced distally on the inner 

 side and bears a stout spine which reaches almost to the end of the limb. The next 

 two segments are short and sub-equal, and together equal in length to the terminal 

 segment, which bears three apical sete and one lateral. 



The fourth legs are slightly longer than either the third or the fifth (figs. 18 to 20). 

 In each the basis bears several long setae, and the terminal segment is very short, 

 with a rather stout claw. 



The uropods (fig. 27) are rather less than one and a-half times the length of the 

 terminal somite. The peduncle is about two-fifths of the length of the sub-equal 

 rami. The endopod bears a few spinules and plumose seta? on its inner edge. The 

 outer edge of the exopod is obscurely serrate, its inner edge unarmed. The apices 

 of both rami (fig. 27. A, b) have a rather peculiar structure. The endopod tapers 

 down to a minute rounded knob, beyond which projects a flattened or rather winged 

 spine consisting of a central rachis with a striated wing or web running down either 

 side. The tip of the exopod is bifid, the two points close together, the lower having 

 the same structure as the tip of the endopod, the upper differing in being without the 

 knob-like process. 



Adult Male, 9 - 3 millims. in length (figs. 3, 4) : 



Carapace much narrower than in the female, its greatest width about five-ninths of 



