Miscellaneous. 475 
not, however, succeeded in observing glandular orifices in the 
lary nx, we may believe that it is common to the two mucous 
membranes with respect to which it is intermediate. The posterior 
median group is likewise quadrilateral in sections, The two 
lateral groups on each side are quite unequal as regards both volume 
and shape. The larger one occupies the pharyngeal commissure, 
and is therefore distinctly lateral in position ; it is composed of 
well-developed and very bulky lobes. The second lateral group is 
situated between this and the posterior [median] group; it is 
composed of flattened lobes and forms an extended sheet, which, 
in certain specimens, may Join the posterior group. 
Of these glands, the lateral groups of the commissures are much 
the more important and descend into the cesophagus, where they 
form two wonderfully well-developed masses—especially in the 
duck, in which they continue as far as the glands of the crop, 
which are recognizable by the special characters described by Prof. 
Renaut. 
From this anatomical study it may be gathered that the salivary’ 
apparatus of birds is but seldom arranged in the form of bulky 
glands, but that it exists none the less and is very well developed, 
forming sheets beneath the mucous membrane, which are sometimes 
confluent. Since adipose tissue is altogether rare in the heads of 
birds, the anatomical character of these glands can be seen to 
perfection. They locate themselves where they can, between 
mucous membrane, bone, and muscle. This explains their apparent 
absence and their neglect by anatomists. Although this is apart 
from our subject, we might note here the presence of limited groups 
of glands in the nasal fosse of the fowl. 
Il. SrructurE oF THE GLanps.—As we have already stated, the 
glands are composite tubular organs. They arise first as a swollen 
bud which becomes hollowed out, and, instead of producing 
agminated swellings at its periphery, as in the case of the salivary 
glands of mammals, transforms itself into a sac, which bristles with 
papillary protuberances ; hence we get three stages in these glands, 
stages which can be easily followed in the same animal, for we 
always find very small lobules side by side with others of full size 
(a condition which is likewise not met with in mammals). In its 
first stage the gland is utricular, scarcely composed of protuberances ; 
it is, on a small scale, the reticulum of the stomach of the ox. In 
a more advanced stage these protuberances have risen; they have 
contracted the lumen of the glandular cavity and are charged with 
secreting cells, the result of which is that each protuberance or 
papillary compartment encloses a short tubular gland. Finally a 
third stage shows these glands individualized and uniting in a 
common excretory duct with a differentiated epithelium. The 
development of these villous and very vascular structures perhaps 
explains the fact, mentioned by M. Ranvier, that the lobes which 
are thus formed, aad which attain the size of the head of a small 
pin, are not found to be each enveloped in a distinct basal mem- 
brane. 
