338 Remarks on the Natural History of Fishes. 
would very naturally be expected of him to whom you have 
ever entrusted the care of the subjects upon which the work in 
question treats; and with this feeling, I have thrown together 
the following observations, which I now offer without further 
remark. 
Commencing with the Cartiiacinous Fisnes, the first ten pa- 
ges are occupied with the history of two foreign species of Petro- 
myzon, neither of which is found in our waters. 
The marinus and fluviatilis should have been Americanus and 
nigricans ; both of which were accurately described by Le Sueur 
in the “'Transactions of the Philosophical Society” in 1818— 
fifteen years before the appearance of this work. These two for- 
eign species are accompanied by figures copied from the German 
plates of Strack; and one or two points require to be noticed. 
It is well known that one of the characteristics of this ge- 
nus is “its seven branchial orifices.” Now it happens, that the 
engraver of Strack’s plates thought that six would suffice, and 
accordingly omitted one in his figure. The American copy- 
ist, while he has attempted to exhibit the very attitude of the fish, 
has carefully followed his original, and the specimen before us Is 
minus a branchial hole. The German did however continue the 
dorsal fin to the caudal, as is natural. The plate before us repre- 
sents it as terminating at some distance in front of that 
_ The plate of the second species exhibits in Strack the true 
number of branchial openings; this copy has but five! 
I suspect that foreign ichthyologists will scarcely pardon the 
presumption which would assert that these two species, which are 
ribed as distinct by Linneus, and have been thus acknowl 
edged by all ee naturalists, “are to all intents and put- 
poses the same fish.” 
The thirty four following pages contain the order SeLacHi. 
In the prefatory remarks to this order, Dr. Smith observes, that 
the male shark may at once be recognized by the appendages = 
the ventrals, though he says “their use is totally unknown.” 
Had he consulted standard works on the subject, he would have 
found that these appendages were called “claspers ;” and know- 
ing that the female did not possess them, their use might with- 
out much stretch of the imagination be inferred. 
Eight species of sharks are here catalogued. The Scyllium 
canicula and catulus 1 have never seen, nor heard of, on our coast, 
