94 Maddox, on Parasites of the Common Haddock. 
at the other spot — p. o', pulsating much faster than the 
opposite p. o'. I am not aware of these being noticed by 
former observers. They were shown to others. I expect 
they are valvular folds, and connected with some arrange- 
ment of vessels, of which I could only find faint indications 
here and there, and which may belong to the vascular system, 
the trunks of which, Mr. Goodsir states, are most apparent at 
the lower third of the body. 
The large oval or globular masses removed from the 
interior of the animal by the dissecting needles, and placed 
in the compressorium showed a distinctly cellular or seg- 
mented structure. The lower or male (?) organ removed, gave 
under compression little more than mere outline. The twisted 
condition the creatures often die in, and the apparently dis- 
turbed position of the internal organs with their delicate struc- 
ture, add a considerable difficulty in distinctly ascertaining the 
exact relations of the various parts. It is by examining a large 
number of specimens, which I have done, that we shall 
possibly arrive at anything like a correct description. In 
the integument, both circular and longitudinal fibres and 
very numerous nuclei are evident, and throughout the whole 
interior of the body, in many cases, a kind of loculated 
appearance, probably from sarcode bands passing in various 
directions presented itself. 
In the glutinous textures covering the brain I found only 
two parasites, none in the brain or spinal cord or canal, none 
in the textures of the eye, one on the optic nerve ; and 
between the optic lobes, forming a depression in one of 
them, was a small brownish-looking spot, which, when 
examined, showed groups of, and single, yellowish-looking 
bodies of variable size, but no distinct structure : they ap- 
peared to be scattered in the nerve substance. 
According to the opinion of many the encysted entozoa are 
regarded as immature parasites, or in their pupa condition, 
and doubtless this may be the case ; but how far the peculiar 
creature under consideration has deviated or passed to a 
higher grade, and become partially sexually mature, I cannot 
say, hut venture to hazard the following suggestion : — That 
we have here, as in other Distoma, a hermaphrodite creature, 
which, in its progress towards a reciprocal sexual maturity, 
yet carries on self-impregnation, so that, at the death of its 
host, and thus within a moderate time, (I have seen them 
alive in fish more than forty-eight hours dead, probably three 
days,) of its own death, impregnated ova may be set free to 
again become, perhaps, Monostomum embryos to pass through 
a Cercarial stage, or the lowest phase of a Trematode life. 
