362 The Philippine Journal of Science ish 



The fingers and palm are more nearly of the same length in 

 the females, the palm being one and two-fifths times as long 

 as the fingers in the largest individual. All of the male in- 

 dividuals, except the three smallest (Nos. 1, 2, 3), have both 

 fingers of the chelipeds covered with felted hair, a condition 

 which is not found in the females. The fingers of both males 

 and females are slender, and each has a rather low cutting edge, 

 extending from the teeth to the tip. The youngest males (Nos. 

 1 and 2) and all the females, except No. 25, show 2 teeth on 

 the mobile and 1 tooth on the immobile finger. In No. 25 only 



1 tooth is seen, and this is situated on the mobile finger. The 

 males, Nos. 3 to 13 and 22 to 24, inclusive, show 2 teeth on the 

 mobile finger and 2 on the immobile, but in the young mature 

 males the teeth on the immobile finger are increased in number 

 by the addition of 2, 3, or even 4 confluent teeth, which are 

 situated between the most proximal of the two teeth just men- 

 tioned and the joint, a condition which is characteristic of 

 mature males in some other species at least. 



The palm is almost cylindrical, that of the smallest measuring 



2 by 2.5 millimeters at its middle and that of the large male, 

 No. 20, measuring 4.5 by 5 millimeters at a similar point. 



The carpus is cylindrical in cross section, and increases grad- 

 ually in diameter passing from the proximal to the distal end. 

 It is shorter than the propodus and longer than the palm, but it 

 does not increase in length so fast as does the palm. In the 

 mature males there is a slight swelling of the carpus a little 

 posterior to the distal end. 



The proportion of the merus to the carpus ranges from 1 : 1.33 

 to 1 : 1.77, and the measurements indicate that the carpus grows 

 faster than the merus. The latter is slightly longer than the 

 palm in the young but slightly shorter in old individuals. It is 

 always shorter than the carpus and longer than the fingers. The 

 merus, which is flattened dorsoventrally along the proximal part, 

 becomes almost cylindrical and of greater diameter at the distal 

 part. 



As in other palaemons, the merus grows faster than the 

 ischium, so that the proportion between the ischium and merus 

 increases with increasing body length. In the young mature 

 males this increase is especially evident. The ischium is flattened 

 dorsoventrally, the upper and lower surfaces being divided into 

 two regions by a median longitudinal groove. 



Third, fourth, and fifth legs. — The third, fourth, and fifth legs 

 extend with their dactyli beyond the tip of the antennal scale 

 in young individuals of both sexes. In older individuals as much 



