."60 MB. W. r. LANCHESTBB ( >N ill K DeO. 3, 



its tip overlapping the dactyl when the fingers are closed. In both 

 hands the dactyls are strongly bent — almost to a right angle — at 

 their tips. The fingers in the other male are normal, the tips being 

 slightly bent and just crossing. 



The rostrum of the larger male is broken off near the carapace ; 

 that of the smaller bears 12 teeth above and 4 below : in both (he 

 first four teeth lie on the carapace. The latter is thickly covered 

 with small spines. The tips of the fingers are (in formol) violet- 

 coloured. 



77. PaljEMOn xir-poxExsis de Haan. 



Palcemon nipponensis, de Haan, Crust. Japon. p. 171 (1830); 

 Ortmann, Zool. .Tahrb. Syst. v. p. 713, pi. .xlvii. fig. 4 (1891). 



hoc. Tale Sap. 



Four adult males and two adult females ; ten young specimens. 

 Length from 37 mm. to 17 ram. 



I have not seen specimens of the P. acanthurus Wiegmann 

 from Brazil and Haiti, but, to judge from the description of this 

 species, it is a form very closely allied to that of de Haan (vide 

 P. forceps, M.-Edw. Hist. Xat. Crust, p. 397; v. Martens, Arch, 

 f. Naturg. xxxv. p. 28 ; and P. acanthurus, Ortmannn, t. c. p. 720). 

 In comparing the specimens here dealt with with the different 

 descriptions of the two species it appears that the chief specific 

 differences may be arranged under four heads, thus : — 



P. nipponensis. P. acanthurus. 



i. 2-4 teeth on under edge of rostrum. 4-7 such teetli. 



ii. "2nd legs in adults with irregular 2nd legs in adults with small teelh 



small teeth : fingers hairy. tending to be ranged in rows ; 



fingers with thick pubescence, 



iii. Telson with 2 lateral spines, of Inner lateral spines not more than 



which the inner is about 5-6 times 3 times as long as outer ; between 



as long as outer : between the inner these several non-feathered hairs, 

 spines 2 feathered hairs. 



iv. Dtstr. Japan, China. Distr. Brazil, Haiti. 



I will take the first three points in order in their relation to 

 these specimens ; the distribution, of course, agrees with that 

 of P. nipponengis. 



i. I give the tooth-formula of the rostrum in each case, giving 

 that of the adults first : — 



11 . 11 t 11 10 6+1 7 + 1 ., 6 + 1 6+1 



- , two . . two ^> j ; — , — j-> three ^ . two —^ . 



5+1 . 5+1 

 -^tWO-g-. 



From these formulae it may be seen that the number of teeth 

 on the under edge is variable as between the two species, and 

 does not form any specific criterion. It also appears, and this 

 does not seem to have been mentioned by earlier authors, that in 

 the younger individuals the full number of teeth on the upper 



