AND AMERICAN RURAL SPORTS. 
291 
neighbouring woods and mountains. I intend now to de- 
scribe a beautiful little Helicina, found by James S. Craft, 
Esq., last year, while rambling over the hills not far from 
the mouth of our creek. The Helicina is by no means a 
common shell in the United States, and has never before 
been discovered so far to the north. It has, indeed, so 
much the character and general aspect of a West-India 
species, that I suggested a doubt on this subject to Mr. 
Craft, who thus replied to my inquiries: “Of this fact 
rest assured; it is a native of our own hills, whether an 
emigrant from the West Indies may have been its progeni- 
tor or not. I found the individual you have alive, and 
have since discovered several others.” Mr. Say, in his 
excellent work on American Conchology, has described 
and figured two species of Helicina; the one from Florida, 
which he calls orbiculata, somewhat resembles our 
species. 
Helicina Rubella. — Green . 
Shell more than one-fourth of an inch broad, subglobose; 
spire slightly elevated, conical; whorls five or six, with 
minute oblique striae; sutures slightly impressed; epider- 
mis smooth and of a light brick-red colour; aperture irre- 
gularly lunate, or semi-elliptical; outer lip white, callous, 
and partially reflected near the base; operculum, corne- 
ous, smooth. 
I will conclude this paper by describing another little 
shell, to which I have applied a very big name. It is 
quite common in the fresh water streams in the mountain- 
ous regions of Pennsylvania, but I think is not to be met 
with near the Atlantic. 
Paludina Alleghanensis. — Green. 
Shell conical, spire elevated and rather obtuse; whorls 
four, rounded and nearly smooth; the ultimate whorl the 
largest; mouth oval, slightly angular near the upper part 
of the peristome, where it adheres to the body-whorl, 
umbilicus none; epidermis dark brown colour; length two- 
tenths of an inch. Fine specimens of this shell are in the 
Cabinet of Mr. W. Hyde. 
ON THE PHENOMENA OF HYBRID ANIMALS. 
It may be laid down as a general rule, admitting of 
very few exceptions among quadrupeds, that the hybrid 
progeny is steril, and there seem to be no well-authenti- 
cated examples of the continuance of the mule race beyond 
one generation. The principal number of observations 
and experiments relate to the mixed offspring of the horse 
and the ass; and in this case it is well established, that the 
male mule can generate and the female mule produce. 
Such cases occur in Spain and Italy, and much more fre- 
quently in the West Indies and New Holland; but these 
mules have never bred in cold climates, seldom in warm 
regions, and still more rarely in temperate countries. 
The hybrid offspring of the female ass and the stallion, 
the ymoi of Aristotle, and the hinnus of Pliny, differ 
from the mule, or the offspring of the ass and mare. In 
both cases, says Buffon, these animals retain more of the 
mother than of the father, not only in the magnitude, but 
in the figure of the body; whereas, in the form of the head, 
limbs, and tail, they bear a greater resemblance to the 
father. The same naturalist infers, from various experi- 
ments respecting cross-breeds between the he-goat and 
ewe, the dog and she-wolf, the goldfinch and canary-bird, 
that the male transmits his sex to the greatest number, and 
that the preponderance of males over females exceeds 
that which prevails where the parents are of the same 
species. 
The celebrated John Hunter has observed, that the true 
distinction of species must ultimately be gathered from 
their incapacity of propagating with each other, and pro- 
ducing offspring capable of again continuing itself. He 
was unwilling, however, to admit, that the horse and the 
ass were of the same species, because some rare instances 
had been adduced of the breeding of mules, which he at- 
tributed to a degree of monstrosity in the organs of the 
mule, for these, he suggested, might not have been those 
of a mixed animal, but those of the mare or female-ass. 
“ This,” he argues, “is not a far-fetched idea, for true 
species produce monsters, and many animals of distinct 
sex are incapable of breeding at all; and as we find nature, 
in its greatest perfection, deviating from general princi- 
ples, why may it not happen likewise in the production 
of mules, so that sometimes a mule shall breed from 
the circumstance of its being a monster respecting mules?” 
Yet, in the same memoir, this great anatomist inferred, 
that the wolf, the dog, and the jackal, were all of one 
species, because he had found, by two experiments, that 
the dog would breed both with the wolf and the jackal; 
and that the mule, in each case, would breed again with 
the dog. In these cases, however, we may observe, that 
there was always one parent at least of pure breed, and no 
proof was obtained that a true hybrid race could be per- 
petuated; a fact of which we believe no examples are yet 
recorded, either in regard to mixtures of the horse and ass, 
or any other of the mammalia. 
Should the fact be hereafter ascertained, that two mules 
can propagate their kind, we must still inquire whether 
