INTEGUMENT OF NECTURUS MACULOSUS 529 
of gland in the skin of Proteus, and this corresponds with the 
mucous type of other authors. His results were confirmed 
later by Leydig (’76 a) and Phisalix (12). Also Calmels (’82, 
83), Leydig (’92), Junius (’96), and Muhse (’09) describe one 
kind of gland and believe that the mature gland is of the granular 
type, regarding the so-called mucous glands as younger stages 
of it. 
2. Morphology. a. Distribution, form, and position. Under 
this heading (a) are considered the mature glands, which are 
uniformly present in every preparation of integument. Over 
the general body surface of Necturus the glands, as in all other 
Amphibia, are of the simple alveolar type. Within the cloaca, 
large groups of long tubular glands, typical of all urodeles, are 
found. No glandular pads, such as have been described for 
tree-frogs and other Anura, are found on the hands and feet. 
The digits, unlike those of Salamandra atra, Triton, Bufo vari- 
abilis, and Alytes obstetricans (Gaupp, ’04), are entirely free 
from glands of either kind. Also on the ventral surfaces of the 
hands and feet, glands are seldom found and none are present 
on the gill trunks or within the gular fold. Over the remaining 
parts of the body, however, both granular and mucous glands 
are found in more or less abundance. The glands in Necturus 
are never grouped and there is no tendency toward specialization 
in any region, except within the cloaca. Granular glands are 
largest and most plentiful on the dorsal surface of the body and 
in regions along the dorsal and ventral edges of the tail. On 
the venter, the mucous glands are more abundant than the 
granular and very large mucous glands are found around the 
margin of the cloacal opening. There are few alveolar glands on 
the arms and legs, and all are small. 
As has already been stated, all the glands except those in the 
region of the dorsal and ventral edges of the tail le in a spongy 
connective tissue, the intermediate layer of the dermis (figs. 6, 
12). They consist of three parts: duct, collar (‘intercalary © 
region,’ ‘Driisenhals,’ ‘Schaltstiick’), and alveolus. The ducts 
of both mucous and granular glands pass perpendicularly through 
the outer layer of the dermis and the epidermis. The collar is 
