NO. 1350. NA TURA L IITSTOR Y OF THE ISOPODA -HIGH A RDSON. 



69 



The segments of the abdomen are distinct on the dorsal side. The 

 hiteral mari^ins of the first five se<j;iuents arc strai<;lit. 'Ilic sixth oi' 

 terminal segment is narrow, elongate, and has a slight emargination 

 in the middle of the posterior margin. 



The pleopoda are five pairs of doulde-branehed appendages, the 

 inner branches of the lirst pair ))eing the largest 

 and overlapping in the middle ventral line. Tlie 

 uropoda are wanting. 



The tirst pair of incubator}^ lamelhe ai'e large 

 and extend al)out half the length of the ventral 

 side of the thorax. In fact all the lamella^ are 

 quite large, and encompass the marsupiiim, leaving 

 only a comparatively small opening into the pouch. 



All the legs have an extremely high expansion or 

 carina on the basis. 



The male has the thorax distinctly segmented, 

 the segments not being widely separated at the 

 sides. Body of male short and thickset, being 

 onl}^ twice as long as wide. 



The abdomen is a little more than one and a half 

 times broader than long. The segments of the ab- 

 domen are only indicated at the sides, being fused in the middle of the 

 dorsal surface; the}' gradually decrease in size to the sixth or last, 

 which is a narrow piece situated between the two lobes of the tifth 

 segment and which does not reach to the extremity of those lobes. 

 Eyes present. Boch' with markings of brown. 



Six specimens of this species were taken by the U. S. Fish Com- 



FlG. 49.— PROBOPYRrS 

 BITHYNIS, MALE. X 41. 



Fig. 50.— Probopyris bithynis. a, porsai, view of female; I>. ventral view of same, x 8. 



mission steamer AlhatrofiS from the Mississippi River near the Expo- 

 sition Grounds in New Orleans, Louisiana. Parasitic on Bithynis 

 oJiionis (Smith). 



Type.—C^i. No. 29089, U.S.N.M. 



About r> specimens which should ])r<)]>ably he referred to this 



