ix, d, 4 Coivles: Palaemons of the Philippine Islands 367 



into an upper wider and a lower narrower region by the usual 

 ridge. The dental formula varies somewhat I — ' ' . ' — j. 



First pair of legs. — In young males about one-half of the pro- 

 podus, in the middle-aged males the whole of the same segment, 

 and in the old males the tip of the carpus extends beyond the 

 antennal scale. 



Chelipeds. — The chelipeds of the young specimen, No. 2, are 

 equal in length, but in all the rest of the specimens in which 

 the chelipeds are present they are unequal in length. This 

 inequality seems to increase with age, and it seems probable 

 that it is not due to injury and regeneration. Only in the mature 

 males, Nos. 7 and 8, are the chelipeds as long as the body. In 

 the youngest male only two-fifths of the carpus extends beyond 

 the antennal scale, while in the mature males from one-fourth 

 to one-third of the merus may be seen beyond it. 



The fingers of the youngest male, No. 1, are longer than the 

 palm, slightly older specimens show the fingers to be a little 

 shorter than the palm, and the old mature males have fingers 

 which are much shorter than the palm. In specimen 8 the 

 proportion of the fingers to the palm is 1:1.66 (left cheliped) 

 and 1:1.44 (right cheliped). Thick hair is not present on the 

 fingers of the youngest specimens, Nos. 1 and 2, but it makes 

 its appearance on both fingers in slightly older individuals. The 

 mature males have a thick coating of hair, which covers all but 

 the tip of the mobile finger. The immobile finger bears a small 

 patch of hair, which is limited to a narrow region extending 

 as far forward as the middle of the finger on both sides of 

 the cutting edge. Four broad and inconspicuous tubercles bear- 

 ing a few stiff hairs are present along the inner side of the 

 cutting edge of the immobile finger. These are situated on the 

 swollen distal half, and are only seen in the mature males, Nos. 

 7 and 8. The mobile fingers of the specimens just mentioned 

 have 3 long low tubercles along the inner side of the cutting 

 edge. They are situated on the distal half of the finger. The 

 keel of the cutting edge is well developed but low in the young 

 and middle-aged individuals, and it becomes reduced to a raised 

 line in the mature males. The youngest male, No. 1, shows 2 

 teeth on the mobile finger and 1 tooth on the immobile finger, but 

 these may be seen only through a strong lens. In specimen 

 3, the beginnings of 1 or 2 confluent teeth posterior to the large 

 tooth of the immobile finger are present. In the mature males, 

 Nos. 7 and 8, there is an indication of the beginning of a 



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