INTEGUMENT OF NECTURUS MACULOSUS 495 
The preceding description has been limited entirely to the 
common elements which form any ordinary stratified epithelium. 
Besides these, many specialized structures are present. Large 
highly developed unicellular glands, shaped somewhat like 
Indian clubs, are found at frequent intervals over almost the 
entire body. These cells rest on the upper dermal layer and 
extend far up into the epidermis, displacing the ordinary epi- 
thelial cells. Goblet cells, highly branched black chromatophores 
and both pigmented and non-pigmented wandering cells are 
seen in greater or less abundance in many regions. Each of 
these special elements will receive consideration below. 
B. Cuticular layer 
The form of the cells comprising the cuticular layer is highly 
variable. The cells may be cylindrical, cubical, or even lens- 
shaped. The cell limits were easily recognized in all preparations. 
No mitosis was noted, but in a study of the ‘casts’ of this layer, 
double nuclei were noticed within single cells. It was impossible 
to tell whether they represented two separate nuclei or whether 
the appearance was due to a deep circular constriction. If one 
wished, this condition could be interpreted as evidence of amitosis. 
Schuberg (’92) described in the horny layer in the toad, binuclear 
and trinuclear conditions, the result, as he believed, of direct 
division. 
1. Cuticular margin. a. In other Amphibia. The special 
feature of the upper layer of epidermal cells is the peculiarly 
differentiated outer margin, which, when well developed, is 
quite resistant to ordinary stains and shows very fine vertical 
striations. This striated zone has been repeatedly described and 
under many different names; many varied theories have also 
been advanced to account for the vertical markings. ‘Cuticula,’ 
‘pseudocuticula,’ ‘gestreifter Cuticularsaum,’ ‘poréser Cuticu- 
larsaum,’ ‘Randsaum,’ ‘Basalsaum,’ ‘Staibchensaum,’ ‘eine von 
Porenkanidlen durchsetzte Membran,’ ‘Deckplatte’ and ‘plateau 
striée,’ are some of the more descriptive terms which have been 
applied to this structure by early writers. 
