152 
Harley, on Cuta7ieous Respiration. 
spherical portion of these bottle-shaped organs^ which lies in 
the cutis vera immediately under the pigment layer^ is sur- 
rounded by a number of blood-vessels. When the blood- 
vessels are injected^ they are seen to be congregated in the 
immediate vicinity of the cavities, and sparingly distributed 
throughout the intervening spaces. In this respect their ar- 
rangement bears a striking resemblance to the distribution 
of vessels round the gland-follicles in the skin of the toad, so 
beautifully delineated by Mr. Rainey/^' and by Eckhard. The 
bottle-shaped cavities in the frog's skin are not, however, to be 
confounded with the large gland-follicles of the toad. They 
have little analogy to each other, and Mr. Rainey has even 
gone so far as to say that no organs like those which I have 
described as the cutaneous follicles of the toad, exist in the 
integument of the frog or water-newt.'' On the other hand, 
however, the organs which it is the purport of this communi- 
cation to describe, are to be found in the skin of the water- 
newt. Some even exist in the corium of the toad, but they are 
much less numerous, and are situated between the true gland- 
follicles spoken of by Mr. Rainey. Immediately beneath 
and partly around the blind sacs exists a layer of parallel 
bands, which compose the greater part of the true skin of the 
frog. These bands have been described by previous writers, 
and consists of two sets, — one running parallel to the skin, 
another perpendicular to it. In consequence of the latter 
constricting, or, more properly speaking, binding together the 
longitudinal bands, a transverse section of the skin presents 
a wavy appearance (PI. VI, fig. 6) .f 
The perpendicular bands are described by Ascherson as 
dividing the cutis vera into small quadrilateral fields, which 
he at first imagined to be cavities, until, on adding iodine, 
he found them full of solid matter. He does not appear, 
however, to have noticed the existence of the parallel fibres. 
Czermak,{ on the other hand, observed not only the perpendi- 
cular, but also the longitudinal bands. He speaks of the former 
as being a set of tubes or canals leading from the under to the 
upper surface of the skin, and of the latter as consisting of 
bundles of areolar tissue. With neither of these views am I 
inclined to coincide, for it appears to me that the structure 
of the perpendicular, as well as of the parallel bands, in some 
respects resembles that of smooth muscular fibre, although 
* " On the Structure of the Cutaneous Follicles of the Toad," ' Quar- 
terly Journal of Microscopical Science/ vol. iii, p. 257. 
t Miiller's 'Archiv/ 1841. 
X " Ueber die Hautnerven des Froches," Miiller's 'Archiv,' J 849, 
p. 253. 
