250 Proceedings of the Royal Physical Society. 
body into cephalothorax and abdomen; but in neither of 
these two specimens was segmentation at all distinct through- 
out the length of the body. In one of these males, I made 
out the ordinary appendages of the cephalothorax, namely, 
two pairs of antennz, one pair of mandibles, one pair of 
maxille, and the rudiments of three pairs of maxillipedes, 
The posterior end of the abdomen had a shape which 
reminded one of that seen in some other species of the family 
Lernzopodide. 
Generic Position—UHaving found only a few specimens, 
and these exceedingly difficult to investigate, I have been 
unable to satisfy myself as to the generic position of this 
parasite, though I have evidence, which I hope to strengthen, 
that it belongs to the family Lernzeopodidee. A comparison 
with previously recorded forms inclines me to believe that 
here we have to deal with a new species, and that it will 
furnish fresh links between the several members of this 
family of Copepoda. This family, the Lernzeopodide, is 
regarded by Kurz as one of the most natural among the 
Copepoda; but partly on account of the difficulty in deter- 
mining the arrangement and structure of the mouth parts, 
and partly on account of the difficulty of preservation, the more 
aberrant forms of this family have been somewhat neglected. 
So far the life-history of this parasite is unknown, or how 
it comes to occupy its peculiar position on the walls of the 
vas deferens. It is possible that it entered the male repro- 
ductive duct as a larval form. 
In conclusion, I would here express my indebtedness to a 
fellow of this Society, Mr Lewis Beesly, who assisted me in 
making drawings and in looking over a number of specimens 
in search of these parasites. 
BIBLIOGRAPHY. 
BASSETT-SMITH, P. W., List of the Parasitic Copepoda of Fish obtained at 
Plymouth (with a good bibliography), Jowrnal of Marine Biological 
Association, vol. iv., pt. 2, Feb. 1896. 
Kurz, W., Studien iiber die Familie der Lernzopodiden, Zeit. wiss. Zool., 
vol. xxix., pp. 380-428. 
CUNNINGHAM, J. T., On Stichocotyle nephropis, a new Trematode, Trans. 
Roy. Soc. Hdin., vol, xxxii., pt. ii., 1884. 
