514 A. B. DAWSON 
comparable to those of the urodeles, an upper homogeneous 
layer, an intermediate and an inner dense layer. But Leydig 
(67), Gaupp (’04), Muhse (’09), and Shipley and Wislocki (715) 
have described the dermis of the Anura as divided into an outer 
loose, an intermediate compact, and an inner loose layer. The 
outer loose zone lies immediately beneath the epidermis. The 
outer homogeneous stratum, referred to by Stieda (’65) and 
others, they regard as the limiting surface of the outer loose 
layer. ‘‘Fibers from the outer loose layer terminate on the side 
toward the epidermis in fine branches. This gives the appear- 
ance of a very thin homogeneous stratum, which for the most 
part follows intimately the lower border of the epidermis” 
(Muhse, ’09; p. 330). The inner loose layer, which they include 
in their divisions, is not a true part of the dermis, but represents 
a highly developed subcutaneous tissue, the ‘tela subcutanea’ 
(Gaupp, 704). 
2. In Necturus. Although the subcutaneous tissue cannot be 
properly regarded as a part of the dermis, still it is so closely 
connected to it, that a brief description seems desirable. ‘The 
thickness of this layer is variable. In many places the cortum 
appears to rest almost immediately upon the muscles (fig. 6); 
in other places the subcutaneous layer is highly developed (fig. 
12) and contains lymph spaces, blood-vessels, and the nerves 
which supply the skin. It is usually composed of fine, loosely 
arranged fibers, with an abundance of connective-tissue cells, 
but often the fibers are collected into large bundles which run 
for the most part parallel to the body surface. However, at 
frequent intervals (fig. 12, tis. co’nt’.), they turn and pass per- 
pendicularly through the inner compact layer into the intermediate 
spongy region, where they spread out and become interwoven 
with the bundles found there. 
The inner layer (figs. 6, 12, drm.’’’), while in many cases not 
the thickest region, is by far the most dense. So closely felted 
are the fibers that with ordinary stains the region has the appear- 
ance of a homogeneous mass, and this effect is heightened by the 
scarcity of cellular elements. When stained by Mallory’s method 
or in van Gieson’s mixture the arrangement of the fibers becomes 
