33(3 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
flanks, brown or slate on the dorsal side, and lighter and semitrans¬ 
parent on the ventral side, where a scattered pigmentation gives it a 
mottled appearance. An examination of a living specimen with a 
simple hand lens shows in certain places, especially on and near the 
legs, a close network of integumental capillaries. These capillaries 
are found, by a microscopical examination of pieces of skin taken from 
all parts of the body to be almost evenly distributed over the entire 
surface of the animal. If a bit of skin be taken from any region of 
the body, and then dehydrated and cleared in oil of cloves or xylol, the 
following points are brought out. The thin euticula is perforated 
thickly and irregularly with tiny openings (pi. 26, fig. 12, ex. op.) 
which are found to be the openings of flask-shaped slime glands. 
These openings are of two principal kinds: the commoner form is 
a simple circular orifice, but there occur also, much less frequently, 
triangular slit-like openings scattered irregularly over the body sur¬ 
face. Between and around all these glands are black pigment bodies 
of irregular dendritic shape (pi. 26, fig. 12, pig.), varying in their form 
and arrangement in different individuals, but always more numerous 
and closer together on the dorsal side of the animal. A curious form 
of white pigment body, already noted by other investigators in the 
skin of various other salamanders, is found commonly on the flanks of 
Desmognathus, among the black bodies. 
Partly hidden externally by the pigment, which bears a close relation 
everywhere to it, is the network of capillaries already mentioned. This 
can be seen in almost any fresh bit of integument mounted in water and 
examined under the microscope, but shows much more plainly in the 
integument of a specimen the circulatory system of which has been 
well injected with some colored solution (pi. 26, fig. 12, cap.). In an 
injected specimen the largest integumental capillaries measured 28 
micra in diameter, the smallest 16 micra. 
For the study of the deeper layers of the skin and for its histology, 
sections of the integument and underlying connective tissue were made 
at a plane vertical to the surface. Two such sections are shown in 
plate 26 (figs. 7 and 8). A thin euticula forms the outermost layer 
(cutic.). This possesses a single layer of flattened nuclei but no cell 
boundaries. The epidermis (ep.), directly beneath this, is formed of 
three or four irregular cell layers, the nuclei of which are slightly pig¬ 
mented on their outer sides, the “diffuse pigment ” of Gadow. A 
cutis (cut.) about twice as thick as the epidermis underlies it. At the 
