No. 428.] 
DIEM YCTYLUS VIRIDESCENS. 
647 
As indicated by Jordan (91), and as simple experiments in 
feeding captive Diemyctyli show, probably the strongest sense 
of the newt is either the sense of smell or 
the tactile sense ; the sense of sight is not 
particularly well developed. Now, to return 
to the pits on either side of the head ; upon 
sectioning these pits it was found that a 
number of simple gland tubes were col- 
lected about the bases of the pits, and these 
tubules (Figs. 2, 3, 4), although not open- 
ing widely in the pits when not active, 
may be seen to have places where the cell 
nuclei were drawn out and arranged paral- 


GR, .- 
Fic. 4.— Section of a tubule 
and i 
inactive gland of an adult 
mal iemyctylus. 7, tu 
bule; e, epithelium. x 210. 
lel with the epithelial nuclei; but when the glands are filled 
with secretion a few well-marked openings into the pits may 
be found (Fig. 5). 
peor 


These pits are formed 
2 from simple depressions or ingrowths of 

from an adult male 
tylus, showing the opening 
int bi. g; helium; 
g, gland tubule. x 1s. 
this broadening and 
epithelium, and the epithelium which lines 
the pits does not differ in any way from 
that which covers the surface of the body 
(Fig. 6). The pits were found to begin 
in about half-grown red males or very late 
red females. As adult life is reached 
these pits or depressions become broader, 
and usually deeper, and together with 
deepening there is an increased develop- 
ment of the glands, which become very numerous in adult males. 
The glands are first formed when 
the pits are hardly more than narrow 
insinkings of the skin, and, as Ancel  : 
(1901) states for other skin glands */ ^, 
of Amphibia, they are derived from . -dp A 
the ectoderm. The cells which form * era t 
the rudiments of these glands are E 
derived from those of the insinking, 
or directly from the adjoining sur- * 





£ A 
ates eB 
BED iE a 
a bt 
»- a 
Fic. 6. — Section of a pit in a young red 
male Diemyctylus. e, epithelium; g, 
udim y gl 3 dabunt x 105. 

faces of the skin (Fig. 7). The little masses of cells which 
develop into glands become nearly separated from the epithelium 
