ix, d, 4 Cowles: Palaemons of the Philippine Islands 333 



to the tip of the finger, and it is flattened laterally. 17 It measures 

 2.5 by 2 millimeters at the base in our largest specimens, and is 

 2.5 millimeters high. The proximal tooth is found about midway 

 between the distal tooth and the articulation of the finger. It is 

 flattened laterally, and in the largest males is smaller than, but of 

 the same shape as, the distal tooth. In old males with the enor- 

 mously developed chelipeds there are 4 teeth present on the 

 immobile finger. The distal one, which is conical in shape (3 

 millimeters at the base and 3 millimeters in height) , is the largest, 

 and is situated 4 or 5 millimeters anterior to the proximal tooth 

 of the mobile finger. Also, in younger males and females this 

 tooth is found in front of the proximal tooth of the mobile finger 

 but much closer to it. The next tooth, which is much smaller and 

 less acute than any so far described, touches the proximal tooth 

 of the mobile finger on its posterior side when the fingers are 

 closed. Directly back of this tooth and almost continuous with it 

 is the third tooth, which is still smaller. The fourth tooth is 

 continuous with the third, and might be considered as a smaller 

 cusp of the third tooth. In young males and females and even 

 sometimes in the very old males the fourth tooth is not distin- 

 guishable, but is represented by a short raised piece of the 

 cutting edge. In the oldest male in our collection (320 milli- 

 meters) there is an indication of a fifth or sixth tooth, which 

 might become more distinct in larger specimens. While the 

 toothing in general is much like that of Palaemon carcinus F. of 

 India as described and figured by Henderson and Matthai, 18 

 the teeth in our form seem to be somewhat more robust. A felt- 

 like coat of hair is present on the mobile finger of both males 

 and females, except when they are very young. Specimens in 

 our collection from 100 to 115 millimeters long show no signs 

 of this hair. As a rule, only the proximal one-half of the finger 

 is coated in the young measuring from 115 to 140 millimeters, 

 but as the animals grow older the coat extends gradually until 

 it covers all but the distal one-fourth. Herbst's 19 figure of Pa- 



" In most living palaemons the chelipeds are held so that the immobile 

 finger lies more nearly in a dorsal position and the mobile finger more 

 nearly in a ventral position, but sometimes in preserved specimens the 

 cheliped becomes twisted so that the fingers lie in a horizontal plane. In 

 this paper the immobile finger will be considered as dorsal in position with 

 reference to the mobile finger, and in the case of P. carcinus the long rows 

 of large spines will mark the dorsal and ventral surfaces of the merus and 

 carpus. The ischium remains in about the same position after preservation. 



™Rec. Indian Mus. (1910), 5, 281, PL XV, fig. la. 



19 Versuch einer Naturgeschichte der Krabben und Krebse (1796), 2, Tab. 

 XXVIII, fig. 1. 



