232 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The results which were obtained were to some extent unsatisfactory, owiugtothe 
difficulty of obtaining an abundance of living ova, and the difficulties attending their 
fertilization by artificial means, as well as rearing the embryos. Notwithstanding 
these untoward conditions, a number of novel facts were collected and experiments 
were carried out which must be of great significance in any further attempts at the 
artificial propagation of these immense fishes. Amongst the most important of my 
results, the observation which I regard as of the greatest practical value, is the de- 
termination, by experiment, that it is possible to quickly obtain both living ova and 
spermatozoa from recently-captured fishes by Caesarean section. The only ova which 
I succeeded in fertilizing were obtained from females of the common sturgeon by 
cutting open the abdomen of the still living fish. Forcing out the ova by pressure, as 
practiced with the shad and salmon, is not feasible in the case of the sturgeon, and 
the removal of the ripe ova from the abdominal cavity of the parent fish may be far 
more expeditiously effected by slitting open the body cavity, in the manner usually 
practiced in dressing the carcass for market. 
The milt is most readily obtained in a similar way from the recently captured and 
living ripe males, only that in this case pieces of the enormous testes are cut out and 
the milt pressed from the fragments. The success which followed the usual methods 
of fertilization proves conclusively that vast numbers of embryos could be hatched 
annually from eggs thus obtained and treated. The number of millions which could 
be reared in this way would depend entirely upon the number of trained spawntakers 
promptly on duty when spawning fish are taken by the fishermen, and the extent of 
the facilities for hatching them and protecting them against the attacks of Achlya 
and Saprolegnia, forms of fungi which were found to be most seriously destructive to 
the life of the ova of the sturgeon in moderately quiet waters. 
Other practical information which was obtained related entirely to the manner in 
which the eggs must be treated in the work of artificial propagation. The extent 
and value of the caviare industry was also investigated, as well as the determination 
of the number of species which frequent the Delaware and other Eastern rivers in 
which sturgeons are taken. The important fact was also determined that the common 
sturgeon (Acipenser sturio) is the only species which is at the present time of any 
commercial value in the fishery of the Delaware. It was my good fortune also 
to secure no less than five specimens of the A. hrevirostris of Le Sueur, which has, so 
far as I can learn, not been certainly recognized since that naturalist’s time; recent 
writers have in fact almost uniformly confounded it with the common and far more 
abundant species. This species was originally discovered in the Delaware, and there 
have been, so far as I can discover, no trustworthy identifications of the species from 
any other waters. That it has a wider distribution is probable ; it may be that its 
principal center of distribution is other than the river in which it was first taken. 
The comparative rarity with which it is taken speaks much in favor of this view. 
The embryological data of this monograph have been drawn partly from original 
sources, namely, from the embryos which I succeeded in rearing from artificially fer- 
tilized eggs, and partly from the work of other authors. The embryos of the common 
sturgeon here illustrated are, as far as I have been able to learn, the first of that species 
that have ever been figured. While it may occur to some persons that the attempt 
to complete the survey of the external features of the ontogeny of the sturgeons from 
the work of others is a useless duplication of labor, I wish to here state that it seems 
