Akademie der Wissenschaften zu Berlin. 407 
are found at the Cape of Good Hope, in the South seas, on the coasts of 
New Zealand, and of Chili Many of the other Cyclostomata have a still wider 
range, as well as the peculiarity of inhabiting both fresh and salt water, as the 
Ammocoetes, Petromyzon fluviatilis, and P. planeri, which occur in the rivers of 
Europe ; the P. marinus, which abounds in all the European seas, has also been 
taken in fresh water. They have been found in Japan, Tranquebar, and South 
America. Before he proceeds to the anatomical details, the author gives a ge- 
neral description of the genera Myxine and Bdellostoma, which it is unneces- 
sary to insert. The species belonging to the latter genus are furnished with 
eyes. The Myxine glutinosa, on the contrary, is totally blind, and forms the 
only example hitherto known of a vertebrate animal, not possessed of any visual 
organs. Those animals which are generally called blind are always provided 
with organs which, at least, enable them to distinguish the light, though the eye 
itself is covered by a membrane, as Spalax typhlus, Proteus anguinus, Silurus 
CJECiitiens, Acontias caecus, &c. There are many examples amongst the inverte- 
brata of total blindness, even amongst classes, the generality of which possess 
the power of vision. Then follows a most accurate description of the osteology 
of the Myxinoidea, succeeded by a close comparison of their different organs, 
with the corresponding parts in the cartilaginous, as well as other fishes, and 
the results of a chemical examination of the bones of each. On exposing a por- 
tion of the spinal column of the Squalus Cornubicus to a white heat till all the 
animal matter was consumed there remained in one instance 41,55 , in ano- 
ther, 42,068g, of ashes. These contained a very large proportion of phosphate 
of lime, a portion of sulphate of lime, and evident traces of fluoric acid. Car- 
bonic acid could also be detected. The cartilage of this class of fishes he di- 
vides, according to its internal structure, into four classes. The first is called 
the hyaline cartilage, and is nearly transparent. It is not found in Petro- 
myzon, but abounds in the sturgeons and chima?ra3. The second is the tu- 
bercular calcareous cartilage, and is most abundant in the Plagiostomata. The 
third is the cellular cartilage, which is found in the Bdellostomata, and the 
fourth is termed the ossified cartilage, forming the hardest bones of many of the 
sharks and rays. On calcining the tubercular cartilage of a large ray, there re- 
mained an inconsiderable residuum, which consisted chiefly of phosphate of lime. 
Fluoric acid was also perceptible, as well as carbonic acid, and sulphur ; but it 
appeared doubtful whether the latter was in the metallic form or as sulphuric acid. 
A portion of hyaline cartilage, carefully prepared, left a very trifling residuum, 
which also gave evidence of containing sulphur and phosphorus, combined with 
lime, but not so as to be separable. An analysis of the bones and cartilage of 
Squalus peregrinus, conducted by Chevreul, and apparently with greater accuracy 
than those made by the author, is also given. * We have not room for the de- 
tails which follow of the comparison between the chorda dorsalis of the Cyclos- 
tomata, and that of the higher vertebrata ; but the conclusion the author arrives 
at is, that the spinal column of the Cyclostomata retains the same form and 
condition as that which we find in the embryos of the higher orders of animals, 
during the first days of their conception. The following are the gradations 
which the spinal column undergoes in its structure, ascending from the lower 
to the higher animals. 
* Vide Ann. du Musee d'Hist. Nat. Tom. xviii. 
