550 
DE. A. GUNTHEE’S DESCEIPTION OF CEEATODIIS. 
nected by the vena cava and cellular tissue (Plate XXXIX. fig. 1, g). The outer margin 
of the testicles is sharp, slightly undulated or indented. In one example a deep notch 
almost entirely cuts off a posterior lobe from the right testicle ; therefore it is evident 
that this organ varies considerably with regard to the details of its form, as in other 
Fishes and Batrachians. The greater (outer) portion of the testicle is free, covered by 
the peritoneum, which passes thence over to the intestine. The inner third of the ventral 
surface of the testicle has no peritoneal covering, and is firmly attached to the intestine. 
Its innermost margin is fixed to the side of the lung. 
The structure of the testicle was found not to be identical on both sides. In the left 
testicle three strata can be distinguished on external inspection and by transverse sections 
made about the middle of its length, viz.: — a light liver-coloured substance, forming by far 
the greater portion of the organ ; then a much thinner and narrower stratum of whitish 
colour, lying on the liver-coloured substance along the line of attachment to the intes- 
tine ; finally a still more superficial and still narrower layer of a dark yellow fatty 
blastema which accompanies the vena testicularis. A duct traverses the whitish sub- 
stance from one end of the testicle to the other (Plate XL. fig. 3 & 4, a) ; it is widest in 
the middle (scarcely one sixteenth of an inch), and tapers towards its extremities, with- 
out penetrating to the surface of the testicle ; its walls are perforated by innumerable 
pore-like openings, leading immediately into the canaliculi seminiferi (d). Coloured 
fluid injected into the duct was equally distributed throughout the substance of the tes- 
ticle, through the whitish portion as well as the liver-coloured ; but in the former the 
canaliculi seminiferi were more distinct, visible to the naked eye, densely packed, parallel 
to one another, arranged in obliquely decussating rows. The course and arrangement 
of the canaliculi in the liver-coloured substance of this (left) side could not be clearly 
made out, as it had too much suffered by decomposition ; but on the right side they could 
easily be filled with fluid, at least those nearest to the surface : they run parallel to one 
another, across the testicle, at a right angle to its longitudinal axis ; they have a slightly 
wavy course, do not subdivide, and appear to be equally wide throughout their length. 
The longitudinal duct (a) is present, as on the left side but the whitish stratum, if 
present at all, must be extremely thin, whilst the adipose substance is spread over the 
inner third of this testicle, surrounding the vena cava. In the second example with 
shrunk testicles I was unable to find again the longitudinal duct. 
The vasa deferentia are, with regard to their course and orifices, entirely analogous to 
the oviducts. Their abdominal orifices occupy exactly the same spot as those of the 
oviducts. They run (Plate XL. fig. 1, g 1 ), separated from the testicles by the perito- 
neum, in a slightly undulated course, towards the posterior end of the testis, are inti- 
mately attached to the ventral margin of the ureters (Plate XLI. o, o'), their canal 
remaining perfectly distinct from that of the latter, and finally they terminate in a 
common opening in the dorsal wall of the cloaca (ibid, p, or Plate XL. fig. 2 , g"). 
This opening is separated from that of the ureters by a low fold of mucous membrane. 
In their anterior third they are very thin, but their lumen is nearly 2 millims. wide. 
