1868.] DR. C. SEMPER ON MACROBRACHIUM. 585 



Barbus (Puntius) melanampyx, Day. 



This species Dr. Giiiither* considers identical with Barbus (Pun- 

 tius) grayi. Day, and Barbus [Si/stomus) arulius, Jerdon. 



Whetiier my B. grayi is merely a variety of B. melanampyx I am 

 unable to be quite decided about, not having a specimen of the 

 latter at hand to compare with ; but it certainly is not identical with 

 the B. arulius, as I shall presently show. Dr. Jerdon observes, " I 

 know your Puntius melanampyx well ; I noticed it in my catalogue as 

 Cirrhinus fasciatus." This fish Dr. Giinther has placed as a Ty- 

 loffnathus (p. 62) amongst the doubtful species. But the specific 

 na.me fasciatus is occupied by a species of Dr. Bleeker's f . 



As regards the differences between the Barbus grayi and B. arulius, 

 some easily recognized ones are as follows : — 



B. grayi. D. 3/7-8. A. 2/5-6. L. 1. 20. Four barbels. 

 Lateral line first curves very slightly downwards and then rises op- 

 posite to the commencement of the dorsal fin. Caudal lobed in its 

 outer third or, even, half. 



B. arulius. D. 3/8-9. A. 2/5. L. 1. 23. No barbels. Lateral 

 line curves directly downwards to above the ventral fin. Caudal deeply 

 emarginated in its posterior three-fourths. The rise from the snout 

 to the dorsal is great in the B. fjrayi, but slight in the B. arulius. 



Having been unexpectedly directed to visit the various "anicuts" 

 or weirs in the rivers of the Madras Presidency, for the purpose of 

 ascertaining whether they are or are not causing destruction to the 

 freshwater fisheries, I must defer the continuation of this paper until 

 after my return. 



6. Some remarks on the New Geuus Macrobrachium of Mr. 

 Spence Bate. By Dr. C. Semper. 



The second number of the 'Proceedings of the Zoological Society ' 

 of 1868 contains an article by INIr. Spence Bate on a new genus 

 of freshwater Crustaceans. Having had the opportunity of ex- 

 amining the original specimens of two of Mr. Bate's so-called new 

 species, I found, to my great astonishment, that certainly two, if not 

 three, of these new species are well known, and have been repeatedly 

 figured and described. 



Macrobrachium americanum, Spence Bate, from Lake Amatitlan, 

 is identical with Palcemon jamaicensis, Herbst. To my knowledge. 

 Sir Hans Sloane X is the first author who described and figured this 

 crustacean from Jamaica, as early as 1/25 ; and Parra§ described it 

 in 1/87 as " Camaron cle agua dulce.'" Leach, in his 'Zoological 

 Miscellany.' repeats that it lives in fresh water ; but MUne-Edwards 



* Catalogue of Fishes, vii. p. 133. 

 f Giinther's Catalogue, vii. p. 122. 



t A Voyage to the Islands Madera &c., 1725, vol.ii. p. 271, t. 245. fig. 2. 

 § Descripcion de diferentes piezas de liistoria natural &c., 1787, p. 154, 

 t. 65. fig. 2. 



