514 MULLER ON THE STRUCTURE OF THE GANOIDS, 
If we blow into the abdominal aperture of the oviduct, the air 
rushes out at the urogenital pore. 
In the Sturgeons, the form and position of the abdominal ori- 
fice of the tube are exactly the same. But the tube at this point is 
isolated for a short distance only, it soon terminates in the broad 
ureter which then at the same time becomes an oviduct. In 
male sturgeons the same infundibulum leads from the abdominal 
cavity to the oviduct. M. v. Baer was the first who described 
this interesting fact in the anatomy of the male organs of gene- 
ration of the Sturgeon*. M. Rathket has proved its existence 
in females. Whilst examining this point I met with one cireum- 
stance which had been overlooked by these two anatomists. The 
infundibulum leading from the abdominal cavity to the ureter 
appears in the ureter as a blind sac; in many large sturgeons, 
both male and female, these broad sacs were perfectly closed, so 
as not to allow the passage of air or mercury. This object being 
so large, a blind pouch of the diameter of the little finger, an 
error is hardly possible. In one case, among many, the funnel- 
shaped canal did not form a blind pouch, but opened into the 
ureter. It was in the male generative organs which had been 
removed from a very large sturgeon, and had been made into a 
preparation a long time previously; I also found the infundi- 
bulum open in the ureter of a female Scaphirhynchus Raffinescii, 
Heck.; in both cases it was open on each side. Hence it ap- 
pears that the abdominal infundibula are only open at certain 
times, at others remaining closed. A large female, in which the 
blind pouch of the infundibulum was closed, was found in the 
summer in the river Oder, the ovary contained immature ova 
perceptible with a lens f. 
The Sturgeons have also on each side of the anus an abdominal 
orifice ; this is wanting in Polypterus, as also the communication 
between the cavity of the abdomen and the pericardium; the 
pericardium exhibits merely a deep depression towards the pos- 
terior part. In general the outlet of the anus is anterior to that 
* Berichte der K. Anatom. Anstalt zu Konigsberg, ii. Leipzig, 1819, 40. 
+ Ueber den Darmkanal und die Zeugungsorgane der Fische. Halle, 1824, 
Pe The manner in which the seminal fluid is excreted is still unknown. 
Rathke thought that he discovered oblique canals between the testes and the 
urinary tubes in the Sturgeon. The testes certainly consist of twig-shaped 
seminiferous tubes, which may be seen with the lens, and not of minute vesicles ; 
but they are very confused, and their arrangement and mode of termination 
still remain unknown to me. 
