CRUSTACEA OF THE MEEGTJI AECHIPELAGO. 283 



tions as in tlie largest specimen, and the fingers are of a fine blue 

 colour with white tips. 



As regards the other legs, I may add that those of the third 

 pair are quite as long as the antennal scales, and that those of the 

 fifth pair do not project so much forwards, reaching only to the 

 distal end of the peduncles of the internal antennae. These legs 

 are also minutely scabrous. The propodites of the legs of the fifth 

 pair are still a little longer than the meropodites and about twice 

 as long as the carpopodites. 



The species witli which our P. acutirostris is most closely allied 

 are the following : — • 



(1) Palcemon asperulus, v. Mart., from Shanghai, seemingly 

 differs from P. acutirostris in its rostrum, having only two or at 

 most three teeth of the upper margin situated behind the anterior 

 margin of the carapace ; by the carpopodite of the anterior legs 

 being comparatively shorter, and by the carpopodites of the legs 

 of the second pair being not shorter than the arm. 



(2) P. loninensis, Stimps., from the Bonin Islands. This 

 form is scarcely different from P. acutirostris, and may perhaps 

 prove to be merely a local variety. 



(3) P. japonicus, de Haan, which differs from it by the shorter 

 fingers of the larger hand of the second pair, which are precisely 

 half as long as the palm, and by some other characters. 



(4) P. hrevicarpus, de Haan, also from Japan. In this form 

 the fingers of the larger hand of the second pair are quite as long 

 as the palm. 



P. acutirostris, Dana, has hitherto, so far as I know, been only 

 recorded from the Sandwich Islands. 



157. PALiEMON EQUiDENS, Dana. 



Palsemon equidens, Dana, United States Expl. Exped., Crustacea, 

 i. p. 591, tab. xxxix. fig. 2. 



Four specimens collected in fresh water I refer to P. equidens, 

 Dana. Unfortunately all these specimens have lost their second 

 pair of legs, except one male, in which one of the legs, probably 

 the smaller one, has been preserved ; I can therefore add little 

 to Dana's description. 



The formulae for the teeth of the rostrum of these four spe- 

 cimens are : |, | X' ^^-^ T ' ^° ^^^* *^^® formula is -^^. The 

 first two teeth are placed on the carapace beliind the anterior 



