﻿i.\. D,i Cowles: Palaemons of the Philippine Islands 355 



fresh) which empties into Pasig River near Manila. The one 

 specimen just mentioned was captured in an estero (brackish 

 water) emptying into Pasig River in the city of Manila. It is 

 very probable then that P. philippinensis might be taken in 

 considerable numbers in brackish water. 



Palaemon sundaicus Heller. Plate II, figs. 3 and 3a-/. 



There is in our collection a fairly complete series of a 

 palaemon which may be distinguished in life and sometimes in 

 the preserved condition from other species found near Manila 

 by the beautifully marbled or tortoise-shell-like markings on its 

 chelipeds. This form is probably Palaemon sundaicus Heller, 13 

 although there are certain differences which will be mentioned 

 below. The young specimens in our collection agree very well 

 with the descriptions of de Man and Coutiere for P. sundaicus, 

 but our series contains a number of much larger males exhibit- 

 ing characters which have not been described by Heller, de 

 Man, 34 or Coutiere. 35 I regret that I have not been able to see 

 the paper of Hilgendorf. 88 



A study of the females and the young males in our series 

 shows how closely they resemble specimens of like size described 

 by the authors mentioned above. The shape, length, and dental 

 formula of the rostrum and also the relative lengths of the 

 different segments of the chelipeds are strikingly similar. In 

 our collection the males reach a larger size than the females, 

 the former ranging from 59.5 to 108 millimeters, the latter from 

 53.5 to 89 millimeters. Unfortunately, both de Man and Coutiere 

 had small collections, the individuals of which were mostly fe- 

 males, and in all cases the males which they examined were no 

 larger than the smallest males in our series. 



The fingers of the chelipeds in all of our males except the 

 smallest are covered with felted hair which increases in thickness 

 as the animals become larger. This does not seem to be true 

 of any of the males described by de Man or Coutiere, although 

 it must be mentioned that all of our specimens bearing this 

 felt are larger than any specimens described by these authors. 

 Another difference is that in our series we have males of medium 

 size (young mature males) in which the fingers gape widely 

 and in which the relative length of the segments of the chelipeds 



" Sitzungsber. Akad. d. Wiss., math.-nat. Klasse, Wien (1862), 45, 415. 

 " Zoologische Ergebnisse einer Reise in Niederlandisch Oet-Indien 

 (1892), 2, 437. 



05 Ann. Sci. Nat, Zool. (1900), 11, 332. 



"Land und Siisswasser-Dekapoden Ostafrikas (1899), 130. 



