ISOPODS OF NORTH AMERICA. 



559 



to the extreinitv of those lol)es. Eyes present. Body with markings 

 of brown. 



Six specimens of this species were taken l)y tiie I'. 8. Bureau of 

 Fisheries steamer Alhatro.ss from the Mississippi 

 River near the Exposition grounds in New 

 Orleans, Louisiana. Parasitic on Bithynis 

 ohionls (Smith). 



Tijjje.^C^t. No. 21»(».SH, r.S.N.M. 



About 6 specimens which shoukl probably ))e 

 referred to this species were found in Escondido 

 River, Nicaragua, 50 miles from Bluetields, l)y 

 Dr. C. W. Richmond; they are parasitic in the 

 branchial cavity of Bithynu acanthuvus (Wieg- 

 maiui). 



They dill'er from the type as above described 

 in having no antero-lateral processes to the 

 head of the female; in having patches of black 

 on the lateral margins of all the segments of 

 the thorax on one side of the body; and in 

 having sometimes the third and also the 

 fourth lamella? of the incubatory pouch with patches of black. 



In the male the terminal segment has in some specimens a tendency 

 to be bilobed. 



FiC. Oil. — PROBOPYRrS ] 



THYNisi. Male, x 41. 



PROBOPYRUS ALPHEI Richardson. 



Bopyrus sp.? Fritz ^IfLLEU, Jenai«'lie Zeitsdirift, VI, 1871, p. 68. 



Bopj/rus alphei Giakd and Bonxikr, Bull. Sclent., XXII, 1890, p. 869 (nomen 



nudum). 

 Bopi/rus alphei Richakdsux, Proc. Wash. Acad. Sci., II, 1900, pp. 158-159. 

 Gi/gesp:? H. Y. Wilson, American Naturalist, XXXIV, 1900, p. 358. 

 BopyreUa alphei Bonnier, Trav. do la Station Zool. de Wimereux, VIII, 1900, 



p. 352. 

 Probopyrus alphei Richardson, Proc. U. S. Nat. Mus., XXVII, 1904, pp. 67-68. 



Localities. — Beaufort, North Carolina, on Crangon lieterocliselh; 

 mangroves, Rio Parahy})a do Norte, Brazil, on Crangon heterochselis ; 

 Desterro, Brazil, on an undetermined species of Crangon (Muller). 



The bod}' of the female is broadly oval, its greatest width being- 

 equal to its length, broadened anteriorly and narrowed posteriorly. 

 Head widening posteriorly, its antero-lateral angles being produced 

 into lobes, directed upward. Eyes absent. The thoracic segments 

 have their lateral margins somewhat elevated and contiguous. The 

 abdominal segments are not contiguous along the lateral margins, but 

 are separated hy broad lateral incisions. 



