456 7 Natural-Historical Collections. 
History of the Developement of the River Crab ; by M. RaTUKE, of Dantzig. 
—The germ appears in the egg of the river Crab, even before the egg is brought 
to light, under the form of a small disc, which occupies about the tenth part of 
the vitellus. But, at the moment when the egg is expelled, the matter of this 
germ expands over the whole yelk, around which it forms a kind of cloud. 
After some time this matter is brought together again, but only in a partial 
manner, and so as to preserve the appearance of a multitude of small agglome- 
rated islands. At a later period these small masses dissolve, and the matter of 
the germ expands a second time over the whole of the yelk. It is again col- 
lected under the form of a disc, which, as at first, occupies about the tenth part 
of the yelk. , 
By degrees the germ separates in two lamine, one of which, applied around 
the yelk, corresponds to the mucous layer of the vertebrate animals, and of which 
the other represents the serous lamina. As soon as the two edges of the first 
lamina meet each other, the digestive canal and the sac of the yelk are formed. 
From the other lamina results the wall of the body. There is also a vascular 
lamina, which does not always exist separately, but which is confounded with the 
serous lamina, while, in the vertebrate animals, it is confounded with the mu- 
cous lamina. 
The central parts of the nervous system appear at the internal surface of the 
serous lamina. Proceeding from the brain, we perceive ganglia disposed in two 
close and parallel series, so that there is a pair for each ring of the animal, con- 
sequently six pairs for the organs of mastication, five pairs for the feet, and also, 
probably, six pairs for the tail. Those of the organs of mastication, and of the 
first pair of feet successively approach each other, and are at length confounded 
into two ganglionary bodies placed the one behind the other. The other ganglia 
come close together on the two sides, but keep separate in the longitudinal direc- 
tion. From this it will be seen, that the nervous system of crabs presents phe- 
nomena similar to those which M. Herold has observed in butterflies. 
The vitellus draws near the back, placing itself under the shell. The organs 
of mastication and the feet are at first so like each other, that they might easily 
be mistaken the one for the other. Not only the tail, but also all that part of the 
body which gives attachment to the feet‘and branchiz, are at first bent down- 
wards. The head constitutes the largest part of the body, and in the whole of 
the first pericd, the embryo is ina manner nothing else. This disposition is even 
observed in the Cyclopes, when they issue from the egg. The crab, in leaving 
the egg, carries with it a very large portion of the vitellus, and is nourished by it 
for some time. The genital organs only begin to appear after the embrye has 
left the egg, and the first thing observed is the single ovary or the testicle. Ducts 
(the deferens and oviduct) proceed from these organs, and traverse, only a few 
weeks after birth, the roots of the feet, to make their appearance externally.— 
Ibid. 
New Species of Pterodactyle. (From a communication by Professor Buck- 
land to the Geological Society of London, in course of publication. ) This speci- 
men of pterodactyle was discovered in December last, by Miss Mary Anning, 
and belongs to a new species of that extinct genus, hitherto recognized only in 
the lithographic Jura-limestone of Sollenhofen, which the author considers as 
nearly coeval with the English chalk. The head is wanting, but the rest of the 
skeleton, though dislocated, is nearly entire; and the length of the claws so much 
exceeds that of the claws of the Pterodactylus longirostris and brevirostris, (of 
which the only two known specimens are minutely described by Cuvier,) as to 
shew that it belongs to another species, for which the name of Pterodactylus ma- 
cronyx is proposed ; it is about the size of a common crow, and a drawing of this 
fossil by Mr. Clift accompanies the paper. ‘The author had for some time past 
conjectured, that certain small bones found in the lias at Lyme Regis, and re- 
ferred to birds, belong rather to the genus Pterodactyle. This conjecture is now 
verified. It was also suggested to him, in 1823, by Mr. J. S. Miller of Bristol, 
