ix, d, 4 Cowles: Palaemons of the Philippine Islands 365 



present on the fingers. These structures are described below 

 in a description of a local form of this species. 



The dental formula is — ' n \ J , and the shape and size 



6, 4, 5 



of the head and rostrum agree very well with Dana's figure. 



The rostrum never extends beyond the antennal scale, and is 



decidedly convex over the eye in older specimens. 



The general surface of the body is sometimes dark and some- 

 times light. The color is due partly to closely set brownish 

 pigment spots, which often have a dark reddish tinge, and in 

 addition to this ground color there are patches of yellowish cream 

 flecks scattered over the surface. Usually the tips of the uropods 

 and the telson have a reddish brown color. The characteristic 

 markings of this species (Plate II, fig. 5g) are an almost straight 

 diagonal mark, an inverted V-shaped mark, and 2 marks shaped 

 like an inverted L. These are often bluish in color, and may 

 always be seen more or less clearly on the sides of the carapace. 

 The horizontal limb of the anterior inverted L extends poste- 

 riorly from the anterior border of the carapace, ventral to the 

 spines. The posterior inverted L is situated back of the anterior 

 inverted L, and its horizontal limb is on a level considerably 

 higher than that of the former. The diagonal mark, which 

 really lies on the tissues beneath the carapace and is seen, on 

 account of the transparency of the latter, extends from the point 

 where the horizontal and vertical limbs of the posterior L meet 

 to the posterior margin of the carapace. Finally, the inverted 

 V-shaped mark lies directly above the anterior L. The first and 

 second antennas are never colored blue, but are usually marked, 

 especially in the male, with reddish brown transverse bars. The 

 second legs or chelipeds are mottled in a manner somewhat sim- 

 ilar to that of Palaemon sundaicus, but the coloring is reddish 

 brown and greenish cream, and does not resemble tortoise shell 

 in appearance. 



Palaemon lanceifrons Dana, judging from our specimens, 

 is. distinct from Palaemon idae Heller. The carpus is always 

 shorter than the propodus, and the proportion is about the 

 same throughout the series. Furthermore, the chelipeds of 

 P. lanceifrons are thicker and the rostrum is broader. 



I agree with de Man's statement that P. lanceifrons is distinct 

 from P. sundaicus. The shape of the rostrum, the shape of the 

 different. The color markings and the tubercles on the fingers, 

 fingers, and the distribution of the hair on the fingers are 



