546 A. B. DAWSON 
(00) deseribes the active nuclei as being from five to six times 
larger than those which are inactive, and practically all workers 
have reported a great increase in size in the nuclei of active cells. 
The large nuclei found within the granular glands of Necturus 
have a normal structure and do not show any evidence of degen- 
eration. The nuclear network is irregular but clearly defined 
and the nuclear membrane is distinct. The nuclei vary greatly 
in form. Some are ellipsoidal, while others are greatly flattened 
or elongated. A good idea of the various shapes assumed can 
best be given by a brief statement of the dimensions of some of 
the larger and more characteristic of. these chromatic masses. 
The following measurements of length and breadth were made 
by means of the camera lucida and stage micrometer. Thickness 
was calculated from the number of sections in which a single 
nucleus appeared in a series of sections of known thickness. The 
largest nucleus was 260 » long, but it was only 10 » wide and was 
less than 6 u» thick (fig. 9). Another nucleus was 70 y» long, 44 u 
wide, and 30 » thick. Others were 100, 144, 164, and 172 yu 
longs) 15,15; 40; and’ 12“. wide; and. 8, 10; 10) and Sj thicke 
respectively. The outlines of all were quite regular and there 
was nothing to indicate that these giant forms had been developed 
from a coalescence of several nuclei. Occasionally large irregular 
chromatin masses were found where it was difficult to tell whether 
they represented single nuclei or were due to the close grouping 
of several. In one case the outline of six nuclei could be dis- 
tinguished with certainty. Nicoglu describes similar ‘Kern- 
masses’ in Triton cristatus and states: ‘Diese Bilder koénnen 
mit ziemlicher Sicherheit auf eine direkte Theilung des Zellen- 
kernes bezogen werden” (p: 448). It is probable that in Necturus 
they arise in the same way, but there was no evidence to indicate 
positively whether division took place by the direct or indirect 
method. 
In the adult Necturus the ducts and muscular layers are the 
last parts of the gland to be developed, and they probably make 
their appearance at about the same time. Many large gland 
sacs are found with their epithelium completely transformed 
into secretion and the cell walls entirely gone, but possessing 
