Miscellaneous. 231 
from naturalists; and the very incomplete investigation of it made in 
1860 by M. Keferstein taught us nothing of importance about it. 
The Balanoglossi nevertheless constitute one of the most curious 
of animal types, the position of which in the zoological scale is not 
easy to fix. This appears evidently from the fine work of M. 
Kowalewsky. 
The body in the Balanoglossi (of which two species exist at 
Naples) is vermiform and composed of a series of successive regions. 
The foremost, separated by a constriction from the following one, 
has all the appearance of a head; but a careful examination shows 
that it possesses none of the characters which would justify that 
name. It is no doubt a tactile organ, to which M. Kowalewsky gives 
the name of trunk. It is followed by a sort of muscular collar 
bearing the mouth underneath. The succeeding region is much 
longer, and may be designated the branchial region. We shall recur 
immediately to its singular structure. Further back the body bears 
upon its back two rows of glands (the sexual glands), and then nu- 
merous papillee, which Delle Chiaje took for respiratory organs, but 
which in reality contain blind processes of the intestinal canal : 
this, therefore, might be called the hepatic region. Lastly, the 
terminal or caudal region is smooth and finely annulated. 
The most remarkable peculiarity of the Balanoglossi is the struc- 
ture of the respiratory apparatus. The water which serves for the 
oxygenation of the blood penetrates by the mouth and issues upon the 
back of the animal by two series of apertures placed upon the sides 
of the branchial region. It traverses a very complex branchial 
apparatus, sustained by a chitinous skeleton. This skeleton is 
formed by two symmetrical seriesof vertical transverse plates, 
united in threes by small rods perpendicular to the direction of the 
plates. The whole therefore constitutes a double series of frames, 
upon which ramify the blood-vessels, covered by an epithelial layer. 
The openings of the frames are covered with vibratile cilia. The 
water, after penetrating by the mouth into the pharynx, gets en- 
tangled in the respiratory frames, and issues by the orifices which we 
_have mentioned, the number of which is equal to that of the frames. 
It is impossible, in our opinion, not to be struck by the great 
resemblance of this apparatus to the branchial apparatus of the 
Vertebrata. Certain anatomists have already attempted a compari- 
son of the Ascidia with the Vertebrata, in consequence of their sin- 
gular respiratory apparatus; but in this case the resemblance is very 
much greater. 
No doubt, in other respects, the analogy with the Vermes is 
striking, especially as regards the facies of the animal and the cen- 
tral portions of the vascular system reduced to two principal trunks 
—a dorsal vessel driving the blood from behind forwards, and a 
ventral vessel conveying it in an opposite direction, &c. Neverthe- 
less it appears to be impossible to ascribe to these animals, as M. 
Keferstein has done, a place among the Nemertida, or especially to 
approximate them to the Annelida, as M. Kowalewsky would do. 
For the present it is necessary to elevate the Balanoglossi into a 
