ix, d, 4 Cowles: Palaemons of the Philippine Islands 395 



part of the carapace in the dorsal and lateral regions, but they 

 are not present on the abdomen nor on its appendages. 



The telson ends in an acute spine; the externolateral spines 

 do not extend so far posteriorly as the tip of the telson, but 

 the internolateral spines overreach it by one-half of their length. 

 The 2 rami of the uropods extend the same distance posteriorly. 



Some of the walking legs of this specimen are missing, but 

 in the other old male (No. 1087) they are intact. In the case 

 of No. 1087, the third, fourth, and fifth legs are of equal length 

 but slenderer than those of Palaemon lepidactylus. The third 

 leg just reaches the tip of the antennal scale. One-fifth of the 

 propodus of the fourth leg and the dactylus of the fifth leg extend 

 beyond the peduncle of the second antenna. The propodus of 

 the fifth leg measures 8.75 millimeters in length, and at its middle 

 point it is 0.5 millimeter in diameter. 



The old male, No. 1484, which has been described in detail 

 above, was collected in the settling basin of the Manila water 

 supply by A. L. Day; the old male, No. 1087, was collected by 

 Alvin Seale from Laguna de Bay, near Manila, Luzon. 



Two other male specimens, Nos. 128 and 73, collected in the 

 region of Manila, differ in the size of the body and the form of 

 the large cheliped from the individual described above. These 

 specimens have a somewhat greater body length, the gape be- 

 tween the fingers of the chela is less, the mobile finger is not 

 curved so sharply, the width of the immobile finger at the 

 proximal end (Plate III, figs. 10c and lOcZ for No. 128 and No. 

 73, respectively) is not so great, and there is a more extensive 

 armature of spines on the outer surface of the palm. I consider 

 these specimens, although they are larger than the young mature 

 males, to be "males femenises" or at least specimens in which 

 the mature male form of the chela has not yet developed. Unlike 

 No. 1484, the patches of spines on the carapace are feebly de- 

 veloped, a condition which indicates immaturity. 



The 3 specimens (No. 1451) from Mindanao are very similar 

 to the young mature male. They have about the same body 

 length (one specimen is a little smaller), and the large chela 

 (Plate III, fig. lOe, No. 1451x) is still well armed with spines 

 on the outer surface, but it is approaching more nearly the shape 

 and proportions of the mature male form. The specimen (No. 

 71) from Samar is smaller than the specimens from Mindanao, 

 but the large chela has taken on the mature form and pro- 

 portions. I consider it to be a young mature male. 



One of the specimens from Leyte (No. 1500) measures 86.5 

 millimeters in length (carapace, 27 millimeters). It is an old 



