Aa 
the two I cannot assert, for I have not had an opportunity 
198 LS Ayres on the identity of 
half the length of the maxillaries, densely crowded with short 
teeth. The maxillaries are destitute of teeth. 
One thing more remains, the structure of the branchial 
arches.. It is at the most a matter of very small importance, 
for Artedi’s account simply implies that the outer and inner 
arches may be without tubercles, though it makes no assertion 
at all in regard to them. But small as it is it cannot lv 
allowed to stand, for where it would make a difference no 
difference exists. A double row of tubercles on the second 
and third arches, and a single row on the first and fourth are 
found in all my specimens. 
The last point, therefore, of apparent discrepancy is gone; 
the resemblance is perfect. But I will not dwell upon this 
at present. We come now to consider the abdominal anato- 
my of the fish ; and here if the two species are not identical 
we may expect to find a difference. But it is here that we 
have, as I think, our strongest reasons for believing that the 
gobio is the fish which we find in America. It was this 
which removed every doubt from my own mind and fully 
satisfied me that the three or four nominal species were ac 
tually but one. The liver, the stomach, the ceca, the in- 
testine, the urinary organs correspond in the most minute 
particulars not merely in description, but on actual comparison 
by dissection. If we examine with the greatest care each - 
item in the account of the anatomy which Artedi has given 
us, and then compare them with those which I have present- 
ed, in the description of our own fish, we shall find that the two 
accounts might have been drawn from the same specimens, it 
every respect except one ; that is a part, of what relates to 
the generative organs. Phases in the male, continue distinct 
throughout their whole length, instead of uniting posteriorly 
into one; and neither they nor the ovaries of the female are 
included in a membrane which is * very black." 
- That the organs of the male do not perfectly correspond i 
a male of the European fish, and it may be that # 
