338 The Philippine Journal of Science 1914 



A faint cream-colored band is present on the external rami of 

 the swimmerets. As the males and females (190 to 240 or 250 

 millimeters) grow larger and the chelipeds become longer, the 

 general color becomes a darker blue and the brown, gray, or 

 cream-colored lines on the carapace and abdominal somites and 

 the cream-colored bands on the pleura become much less dis- 

 tinct. The color of other parts still persists, but becomes some- 

 what darker. In old males (240 or 250 to 320 millimeters) with 

 the enormously long chelipeds the color is much less brilliant 

 than in the younger specimens. The dorsal region of the cara- 

 pace and abdomen is brownish green, and the lateral regions are 

 light green or brown. The brown, gray, or cream-colored mark- 

 ings and bands so characteristic of smaller individuals disappear 

 almost entirely, while the orange-colored spots on the abdomen 

 and at the articulations of the segments of the chelipeds, the 

 vermilion color of the ridge on the rostrum, and the conspicuous 

 blue of the first and second antennae usually persist to some ex- 

 tent, but become noticeably darker. The chelipeds appear at 

 first sight a dirty black, but on closer examination they are seen 

 to be a very dark, dirty blue, except in the proximal region where 

 they are greenish blue. The third, fourth, and fifth legs are 

 bluish green in color. The ventral border of the pleura of the 

 sixth abdominal segment shows a distinct orange-colored band. 



A comparison of the color of the local Palaemon carcinus with 

 descriptions and color drawings of Palaemon carcinus from 

 India shows, that while there is a general similarity there are 

 some striking differences. The blue color of the cephalothorax 

 and abdomen is absent, and in its place there are cream-colored 

 bands and other markings. The latter may be present in young 

 specimens of the Indian form. The first and second antennae, 

 so far as I have been able to make out from colored drawings 

 and descriptions, are not blue like those of our local form, and 

 it is of interest to note that in no other palaemon in the Philip- 

 pines with which I am familiar are the antennae colored in the 

 same way as those of the local form of P. carcinus. Finally, the 

 striking changes in color as we pass from the younger specimens 

 to the older ones, if occurring in Palaemon carcinus of India, do 

 not seem to have been recorded. 



Old and young males. — While specialists on the genus Palae- 

 mon are familiar with the fact that the old males in some species 

 look very different from the young males and while it seems 

 probable that the same is true for all species of Palaemon, it is 

 difficult to convince one who is not a zoologist or even a zoologist 



