OF THE STURGEON. 
345 
bands are so small, that they scarcely admit the point of a 
silver probe ; and some are so minute, that the head of a 
common needle only can be inserted into them. 
At my first examination of this structure, I imagined 
that the large or primary bands might be elevated from 
the surface of the membrane, by means of a blunt instru- 
ment inserted beneath. Thisj however, I find not to be 
the case. They are tied down, as it were, by minute 
thread-like bands, similar to the small capillary ones ; and 
which, like the latter, contribute to the formation of the 
minute reticular texture. 
Of the nature of the substance of these intersecting 
bands, I scarcely feel competent to speak with confidence. 
Analogy would lead us to suppose, that they are similar in 
structure to the villo-mucous membranes. I must never- 
theless say, that they have a redder and more fleshy ap- 
pearance, as well as a firmer consistence, than any form of 
villous membrane with which I am acquainted. There is 
further no appearance of villi^ or piles, such as are found 
in the intestinal tube of the mammalia, birds, and some rep- 
tiles. This tissue is short in the inner surface of the duo- 
denum of the sturgeon, while dissimilar to that of the duo- 
denal membrane in other classes of animals, bears a nearer 
resemblance to thaf of the inner surface of the auricle of the 
heart, than to any other part of the animal body. The in- 
dividual bands, or Jusciculi, are perfectly smooth, so that, 
however irregular the surface may seem, its component 
parts are highly polished. The bowel was found filled 
with food in the state of chymous pulp. When this was 
removed, the interstitial cavities were occupied by a good 
deal of mucus, which, however, was easily washed off by 
pure water. 
The upper or gastric extremity of the duodenum is re- 
markable for three orifices which open into it. The first 
