Miscellaneous. 475 



not, however, succeeded in observing glandular orifices in the 

 larynx, 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 quadi'ilatcral in sections. The two 

 lateral groups on each side are quite unequal as regards both volurao 

 and shape. The larger one occupies the pliaryngeal 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 oesophagus, 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 btilky 

 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 fossae of the fowl. 



II. Stkuctuke of the Glands. — As we have already stated, the 

 glands are com])Osite tubular oj'gans. 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 utricidar, scarcely composed of protuberances ; 

 it is, on a small scale, the retindum 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 wliich is that each protuberance or 

 papillarj- compartment encloses a short tabular gland. Finally a 

 third stage shows those ghinds individualiz.ed and uniting in a 

 common excretory duct with a ditfcrentiated c])ithelium. The 

 development of these villous and very vascular structures perhaps 

 explains the fact, mentioned by M. llanvier, that the lobes which 

 are thus formed, and which attain the size of the head of a small 

 pin, are not found to bo each enveloped in a distinct basal mem- 

 brane. 



