DR. A. GUNTHER’S DESCRIPTION OF CERATODUS. 
549 
This is the condition of the sexual organs in a fish 34 inches long, fully mature, and 
evidently caught during the spawning season. I am enabled to add a description of the 
organs in a less developed state (fig. 2) from an example 26 inches long. The extent of 
the ovaries is the same as in the mature example, but a much smaller portion of their 
substance is ovigenous ; at both ends they terminate in strips of a soft substance 
( b , b ' ; c, d) containing a considerable quantity of fat, the posterior strips being narrow 
and tapering in a fine point. The anterior strip of the left ovary (V) is 2| inches long (e), 
and extends, besides, backwards to some distance along the edges of the ovary. The 
anterior strip of the right side is very short, and replaced by the lateral lobe of the liver (l). 
The ovigenous part is from two thirds of an inch to an inch broad, and crossed by trans- 
verse lamellae containing an immense number of very small ova, which are not visible to 
the naked eye. No pigment is as yet deposited in the stroma. 
The oviducts (o, o') are in an equally undeveloped state ; they are of the thickness of 
a pigeon’s quill, and although tortuous in their course, show only a few complete con- 
volutions. The duct of the right side opens by a minute slit (r) at the same place as in 
the mature example ; but the left duct terminates (d) blind in the substance of the non- 
ovigenous strip of the ovary of that side. The specimen was in a good state of preser- 
vation, and neither air nor fluid could be driven through the end of that duct. 
Male Organs (Plates XL. and XLL). 
The following observations have been made on two examples, one of which is the male, 
32 inches long, mentioned above (p. 512). The other example*, although larger (36 
inches), had the testicles considerably less developed, as if they were shrunk ; but I was 
enabled, by injection of mercury, to trace the vas deferens in its entire course, whilst I 
had only partially succeeded in this respect by the use of coloured fluid in the former 
example. 
The testicles are entirely separate from each other ; they are long flat bodies lying- 
on each side of the lung, between the intestine and the walls of the abdomen. The left 
extends from the diaphragm to the middle of the kidney in one example, whilst in the 
other the anterior 2 inches of its length are replaced by an adipose band, as in the adult 
female described above (p. 547). The right does not extend so far forwards, being- 
arrested by the lateral lobe of the liver, with the extremity of which it is intimately con- 
postanal orifices, and that the oviducts had no function, representing merely the remains of the ducts of the 
Wolffian bodies. However, now it it is clear enough that these ducts resemble a Urodelous oviduct in every 
way. But have the peritoneal canals no function whatever? They might be useful for discharging semen or 
ova, which, having lost their way to the abdominal aperture of the oviduct, might injuriously act if retained in 
the abdominal cavity. The presence of a pair of peritoneal openings in Aevpenser, one on each side of the vent, 
is mentioned by several authors. I do not find them in a young example of Acipenser sturio, var. oxyrhynchus, 
24 inches long. In a specimen of Acipenser maculosus, 20 inches long, there is one large aperture on the left 
side, but none on the right. Lepidosteus has two pori abdominales, lateral to the vent. 
* Received whilst this paper was passing through the press. 
