534 A. B. DAWSON 
02; Esterly, 04; Tarchetti, ’04) state that the muscles at their 
upper ends are divided into fibrillae which pass into the epidermis 
and provide for the insertion of the fibers. 
As in other Amphibia, the muscle fibers on the granular glands 
of Necturus are of the non-striated type, greatly elongated and 
spindle-shaped, with long and much flattened nuclei. They are 
arranged in a single continuous layer and lie in a meridional 
direction converging toward both poles. Flattened connective- 
tissue nuclei are often found around the bodies of the glands, 
but, with differential stains, such as Mallory’s and van Gieson’s, 
they are easily distinguished from the nuclei contained within 
the muscle. Sections cut parallel with the surface of the integu- 
ment also show nuclei within the muscle fibers at many different 
levels, with no tendency to such grouping as is described by 
Esterly (’04) in Plethodon. I have followed many fibers through 
their whole extent and have found them to be without exception 
simple spindles, but in many cases it requires two or more fibers 
to reach from the upper to the lower pole of a gland. 
The outer ends of the muscle fibers extend in between the 
cells of the intercalary region, which appears to form a fixed 
point for their insertion. This condition is very similar to that 
described for several toads (Nordenskidld, ’05; Muhse, ’09; Shipley 
and Wislocki, 715), except that the collar in Necturus is never 
so highly developed. There is no evidence whatever that the 
fibers terminate within the epidermis. The muscles were traced 
in sections cut parallel with the body surface and their outer 
ends were found to be indistinguishably blended with the radiat- 
ing cells of the intercalary region, which is of course continuous 
with the epithelial cells above. At their lower ends the muscles 
found on the upper portion of the glands are overlapped by the 
tapering ends of other fibers which lie lower on the gland sae. 
e) Muscles of mucous glands? There is diversity of opinion 
regarding the presence of a muscular layer on the mucous glands. 
The absence of muscle fibers has been used by several writers as 
a character to distinguish them from the granular glands. Many 
investigators describe a muscular layer which is not continuous 
and is easily overlooked unless several sections are studied in 
