322 
The short, bluntly-rounded head (fig. 2) is cut off from the body by 
a distinct groove passing completely round the animal. The dorsal 
surface of the head is slightly curved. The ventral surface is convex 
and bears two pairs of hooks, one on each side of the median mouth. 
This latter is surrounded by a chitinous ring, oval in shape, about 
O' 19 mm. in length, and 0'8 mm. in breadth. The inner hooks are 
single, each consisting of a stout, strongly-curved chitinous procesf; 
0'24 mni. in length. In the outer pair, from the base of each hook 
arises a slightly curved unciform appendage (O'l i mm. in length), as 
in all the hooks of Porocephahts najae-sputatricis, Leuckart. The 
hooks of both the outer and inner parts are jointed at their bases. 
The body exhibits a median line running along the ventral surface 
to the posterior extremity. 
The anus is a small aperture situated at the apex of a small 
papilla at the posterior extremity. Immediately beneath it is the 
genital aperture. 
This species is distinguished from the known species of 
Poroceplialus by the presence of an appendage on the outer pair of 
hooks only. We propose the name Parocephalus cercopilheci in view 
of the host. 
The type specimen of this species is in the museum of the 
Liverpool School of Tropical Medicine. 
