146 Bulletin, VanderMlt Marine Museum, Vol. Ill 



MANN, Revista do Museu Paulista, No. II, p. 212, Est. 1, figs. 10 



and 11, 1897. — Aurivillus, Bihang K. Sev. Vet. Akad. Handl. 



Stockholm, vol. 24, Afd. 4, No. 1, p. 23. 

 Bithynis olfersi Rathbun, Proc. U. S. Nat. Mus., vol. 22, p. 316, 



1900.— Bull. U. S. Fish. Comm., vol. 20, part 2, p. 24, 1901. 

 Palaemon (Macrohrachium) olfersi DeMan, Trans. Linn. Soc. London 



(2), Zool., vol. 9, p. 314, pi. 20, figs. 54-74, 1904.— Ann. Soc. Roy. 



Zool. Malacol. Belgique, vol. 46, p. 109, 1911. — Schmitt, Bull. 



Amer. Mus. Nat. Hist., vol. 53, p. 40, 1926. — ^William Beebe, 



Arcturus Adventure, 1925, p. 228, appendix p. 435. 

 Macrohrachium olfersi Van Name, in "W. K. Vanderbilt's "To the 



Galapagos on the 'Ara\" 



Macrobrachium jamaicense (Herbst). 

 Plate 51. 



Type: Collected in the fresh water streams of Jamaica, and de- 

 posited in the Berlin Museum. 



Distribution : This species is well known in the fresh water fauna 

 of the American tropics on both side of the continents, and has been 

 recorded from Texas, southward, to Brazil on the East Coast, and 

 also from several of the islands of the West Indies, as well as from 

 Lower California to Peru on the "West Coast. 



Material examined: One specimen taken in fresh water stream 

 emptying into Chatham Bay, Cocos Island, Pacific Ocean, January 

 29, 1928, by the "Ara." 



Technical description: Carapace robust, smooth, slightly more 

 than one-third the total of body-length ; rostrum short, only reaching 

 as far forward as the second peduncular article of the inner antennae, 

 acute-tipped, slightly crested, with eleven acute forward-directed 

 teeth on the upper margin besides the apical tooth ; four of these 

 teeth are postorbital on the carapace, a row of cilia anterior to each 

 tooth ; the rostrum extends back on the carapace for two-fifths of the 

 length of the carapace; the under margin of the rostrum has three 

 teeth in addition to the apical tooth ; there is an approximately median 

 longitudinal carina on each side of the rostrum which is continuous 

 posteriorly on the margin bounding the ocular cavity. The antennal 

 spine is short, acute, the lateral margin carinate and bent under the 

 body. The abdominal segments, including the telson, uropoda and 

 pleopoda, are practically identical in shape and proportion to those 

 of M. olfersi. 



