ix, d, 4 Cowles: Palaemons of the Philippine Islands 351 



ters are meant the gaping of the fingers, the proportionately lar- 

 ger teeth on the fingers, the exceedingly long chelipeds, and the 

 roughness of carapace, pleura, sixth abdominal somite, and 

 telson. 



All specimens of P. philippinensis in our collection possess 

 fingers which are shorter than the palm, the next to the smallest 

 male (No. la) showing a proportion of 1:1.22 and one of the 

 largest males (No. 30) a proportion of 1:1.91. In general, as 

 the body grows larger the palm increases in length at a greater 

 rate than the fingers. A similar but much less marked pro- 

 portional increase occurs in the females. The fingers of P. phil- 

 ippinensis show no signs of the long hairs or of the felted hairs 

 which are characteristic of P. nipponensis and P. carcinus, 

 respectively, but all specimens in the collection possess a few 

 scattered tufts of hair, which do not obscure the underlying 

 structures in the least. The teeth, which have been described 

 above as present on the fingers of a large male, can be seen in 

 the youngest males and females only with a high-power magnify- 

 ing lens. They soon increase in size as the animal grows larger 

 (90 millimeters), and become visible to the naked eye. In the 

 small males (No. 3 and others that have taken on the mature 

 form and which for convenience I have called young mature 

 males) the teeth are conspicuous, their size being in proportion 

 to the length of the cheliped. Two teeth on the mobile finger 

 and 1 tooth (the distal) on the immobile finger are present in 

 the youngest males and females (Nos. la and 32). In females 

 and "males feminises" of the size of No. 19 the small teeth back 

 of the proximal tooth on the immobile finger are just beginning 

 to form. The tips of the fingers curve inward at all ages and 

 meet, except in the largest males and sometimes in the young 

 mature males, where the immobile finger curves in much less 

 and extends beyond the mobile finger. In small males, in "males 

 "feminises," and in all the females with the possible exception 

 of No. 39, the fingers do not gape when closed, but in young 

 mature males and especially in the old males the gaping is 

 conspicuous. A keellike cutting edge is found on both fingers 

 of all males and females. This is rather high and sharp in 

 young males (including "males feminises" and young mature 

 males of smaller size) , but it decreases in height markedly with 

 increasing body length in the young mature males and less 

 rapidly in the "males feminises" and females. In the large 

 males Nos. 30 and 31 and the older young mature males Nos. 

 23 and 26, the keel is reduced to an inconspicuous raised line 

 which can be seen only with a magnifying lens. The tubercles 



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