180 first Annual Report 
numbers of the amphipods were infected. It also occasionally 
occurs on certain other large gammarids found near high-tide 
mark. 
Pteronyssus bifurcatus n. sp. 
(Figures 97 and 98) 
Integument strongly chitinized; anterior legs without ‘‘thorns.’’ 
No cuff-like projections on terminal joint of any leg. Male with 
anal suckers well developed; first hind leg of male more developed 
than second. Tarsal sucker larger on this leg than on the others. 
Abdomen shortly bi-lobate, without leaf-like appendages; two bristles 
on each lobe, the medial bristle short, the other one as long as two- 
thirds the width of the body and arising from a prominent tubercle. 
Figure 98. Pteronyssus bifurcatus 
