ISOPODS OF NORTH AMERICA. 



533 



along its outer (longest) border and across its base b}^ a cliitinous rod, 

 Tlio anterior ])lades, in company with the dorsal poi'tions of the third 

 pair of plates, form the funnel-like anterior end of the marsupium. 



"The details of the thoracic segments are shown in iig. 57Sc. The 

 lirst five are crowded together, their fleshy lateral portions strongly 



I'r, Pr. 



I 



Fig. 678.— Stegophkyxuk iiyi-tivs (After Thompson), a, Hermit cRab with para.site attached. 

 X f. b, Anterior portion of head of female (ventra r, side), c, Dorsal view of adult female. 

 X 5J. d, Ventral view of same, x 4J. e, Left maxilliped of adult female, x 10. /, Head 

 OF adult female (dorsal view). X llj. (/, Head of adult female (ventral side), h, Abdo- 

 men and posterior part of thorax of adult female (ventral view). X 51. 



bent toward the head. The lateral parts of tirst four segments end 

 ill a small roughened boss or cushion, on which the roughened third 

 joint of the pereiopod impinges. This cushion may represent a 

 modified epimeron. Internally to this cushion is a flat shield-shaped 

 area which comes in contact with the abdomen of the host. The 



