ISOPODS OF NORTH AMERICA. 



559 



FIG. 611. PROBOPYRUS BI- 

 THYNIS. MALE, x 41. 



to the extremity of those lobes. Eyes present. Body with markings 

 of brown. 



Six specimens of this species were taken by the U. S. Bureau of 

 Fisheries steamer Albatross from the Mississippi 

 River near the Exposition grounds in New 

 Orleans, Louisiana. Parasitic on Bithynis 

 ohionis (Smith). 



Type. Cat. No. 29089, U.S.N.M. 



About 6 specimens which should probably be 

 referred to this species were found in Escondido 

 River, Nicaragua, 50 miles from Bluefields, by 

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

 branchial cavity of Bitkynix acanthurus (Wieg- 

 mann). 



They differ 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 lamellae of the incubatory pouch with patches of black. 



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

 to be bilobed. 



PROBOPYRUS ALPHEI Richardson. 



Bopyrus sp.? FRITZ MULLER, Jenaische Zeitschrift, VI, 1871, p. 68. 



Bopyrus alphei GIARD and BONNIER, Bull. Scient., XXII, 1890, p. 369 (nomen 



nudum). 



Bopyrus alphei RICHARDSON, Proc. Wash. Acad. Sci., II, 1900, pp. 158-159. 

 Gygesp.t H. V. WILSON, American Naturalist, XXXIV, 1900, p. 353. 

 Bopyrella alphei BONNIER, Trav. de 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 Orangon heterochsdis; 

 mangroves, Rio Parahyba do Norte, Brazil, on Crangon heterocJisdis; 

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



The body 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 by broad lateral incisions. 



