ON THE WHIP-WORM OF THE RAT’S LIVER. 89 
It appears that after maturing, the worms do not escape from 
the shells whilst in water, and they live for a considerable time ; 
at the time of writing, April 17, 1893, the eggs placed in water 
two years ago are still alive. Several experiments were made to 
trace the embryos after their introduction to the stomach of a rat. 
It was thought that they would live for a time in the intestinal 
tract. Rats were fed with eggs and killed in two days, in seven, 
and in fourteen days, but these experiments did not give me much 
information. No trace whatever could be found of the worms 
until a fortnight had elapsed after feeding, when they were seen 
to be in the liver, not mature however, Jt would appear then 
that the embryos find their way to the liver atan early date and 
there develop to maturity, pair, and after impregnation the 
females lay their eggs ; the worms then die. 
I have hitherto, neither been able to find the presence of 
Trichocephalus nodosus in the intestinal canal, nor of Trichosoma 
crassicauda in the bladder of rats. No account is given by Cobbold 
or Leuckart, in their excellent treatises on worms, of a parasite 
similar to the subject of this paper. Had they been acquainted 
with it they would, in all probability, have made mention of it. I 
have no opportunity, living in Brisbane, to consult many works on 
helminthology, to find out if this parasite had been described. 
Mr. Henry Tryon has kindly searched through what books there 
are in the Brisbane Museum, and has found one reference 
apparently to it, viz.:—(in the “ American Microscopical Journal” 
of 1889, Vol. x. pp. 193-196, E. A. Bulloch had found the ova 
of a Trichocephalus in the liver of a rat, which he regarded as 
those of T'richocephalus dispar). If the subject of this paper be 
new, I propose to name it 7'richocephalus hepaticus. In length the 
eggs are 5dand 30u to 35u in breadth, they have a perforation at 
each end; mature eggs are exactly the same size. The yelk sub- 
stance is divided in the undeveloped eggs, but all markings dis- 
appear and the yelk is homogeneous in structure in those 
thoroughly developed. The embryo when extruded from the shells 
measure 156y in length and 7 in breadth, with one end blunter © 
