PEOM THE IN DO-PACIFIC AND WEST AFRICA. 309 



In a female specimen of PalcBmon macrobracJiion from Congo of about tlie same size, 

 being 78 mm. long, the legs of tbe fifth pair have the following measurements: — The 

 meropodites are 9'5 mm. long and 0'86 mm. tliick in the middle ; the carpus is 6 mm. 

 long and 0"82 mm. thick at the distal end ; the propjodites are 11'5 mm. long and 0"5 ram. 

 broad in the middle, the terminal joints finally are 3'2 mm. long. In P. macrobrachion 

 the jjropodites of these legs are thus distinctly longer than the meropodites and, like the 

 carpoi^odites, a little more slender than in the male from the River Kribi. The three 

 posterior legs of the male from the E,iver Kribi are covered with scattered microscopical 

 spinules, especially on their upper margin. Hilgendorf has not described the three 

 posterior legs of P. paucidevs. 



[For note received since this paper was in type, see p. 327. — Sec.L.S.] 



Pal^mon (Macrobrachium) jamaicensis (Herbst), var. Vollenhovenii, Herklots. 



(Plates 19. and 20. figs. 38-53.) 



Palcemon Vollenhovenii, Herklots, in Tijdschrift voor Entomologie, i. 1858, p. 96 ; de Man, in Notes 



from the Leyden Museum, i. 1879, p. 178. 

 Palamon jamaicensis (? Herbst), Benedict, in Proc. U.S. National Museum, vol. xvi. 1893, p. 540. 

 PalceiiLon jamaicensis, Herbst, var. Vollenhovenii, Aurivillius, in Bihang till K. Sv. Vet.-Akad. Handl., 



Bd. xxiv. Afd. iv. No. 1, 1898, p. 16, Taf. 2. figs. 1-5. 



The following collection is lying before me * : — 



One adult male from Liberia. (Leyden Museum.) 



Three nearly adult males and two young females, from the Elver Prah, Ashantee. 

 (British Museum.) 



190 specimens of different size, collected in the river at Catumbella, near Benguella. 

 (Private collection.) 



Some time ago Dr. Ortmann, who was enabled to compare adult n:ales of this species 

 from Cameroon with American specimens of P. Jamaicensis (Herbst), finally concluded 

 that the African form was quite identical with the American type (Ortmann, ' Os 

 Camaroes da agua doce da America do Sul,' S. Paulo, 1897, p. 209). Aurivillius, 

 however, who comj)ared ten specimens from Cameroon with one adult individual from 

 Central America, is inclined to regard the African form as a variety of P. jamaicensis ; 

 and I like to follow him provisionally in this opinion, because no American specimens 

 are at my disposal. Nevertheless, I suppose that fresh descriptions of the African form 

 will still be welcome. 



Tlie largest specimen of all lying before me is the male from Liberia. The rostrum 

 (fig. 38), closely resembling that which has been figured by Aurivillius {I. c. fig. 1), reaches 

 to the end of the peduncles of the upper antennae, and is armed above with 16 teeth, a 

 number already observed by that Swedish naturalist ; they are equidistant, but the first 



* Tlio measurements of the body and of the second legs are iiidicatcd iu the Table (p. 322), also the formula) of 

 the rostiimi. The joints of the second logs are measured on their upper surface, the merus, e. </., up to the distal end 

 of the upper mari;in of the iscliium. Nos. 4 and .'j are the Congo specimens described in my paper of 1879. 



44* 



