50 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
Tropidonotus tesselatus Laurenti: In the glandula labialis superior, which 
is somewhat smaller and narrower than that of the natrix, there is present 
the yellowish portion with large follicles. 
Coronella levis Merrem: This species possesses the glandula labialis 
superior, consisting of one grayish and one yellowish portion. 
Coluber viridiflavus var. carbonarius Schreiber, or Coluber flavescens s. 
esculapii: ‘The Aisculapius snake has a less-developed supralabial gland, 
which has, however, two distinct portions, one grayish and one yellowish 
portion. ‘The cells forming the tubules of the yellowish portion are highly 
granulated. ‘The only duct is lined with high, clear, cylindrical cells greatly 
differing from those present in the glandular tubules. The rest of the gland, 
composed of smaller acini, has clear, epithelial cells. Leydig (1873). 
Elaphis virgatus Schlegel: In the rear part of the supralabial gland is 
formed the yellowish portion, which is distinguished, by its firmer con- 
sistency, from the glandula labialis superior proper. Three excretory ducts 
are provided for the latter, but only one for the yellowish portion. The 
structure of the yellowish part is briefly stated here. This portion (yellow) 
is surrounded by a scantily developed connective tissue, beneath which lies 
the lymphatic space with small, irregular, compressed meshes, from above 
to below, which contain some lymphatic cells. The gland consists of 
small, mostly tubular spaces, which, while rather narrow, are quite regu- 
larly built and often present a flattened form. Each of these tubules is 
inclosed in an extremely delicate, soft connective-tissue layer. The interior 
of the tubule is lined with epithelia of cubic shape. The connective-tissue 
capsule of the glandula labialis superior is weaker than that of the yellowish 
portion. 
Ptyas korros Schlegel s. Coryphodon korros Jan: In this species the glan- 
dula labialis superior consists of a grayish and a rear yellowish portion, but 
the transverse sections of the two are described as similar. 
Herpetodryas carinatus Boie: No yellowish part is found in this species, 
although the glandula labialis superior is regularly developed and surrounded 
by a poorly developed layer of connective tissue in which a lymphatic space is 
noticeable. In the place of the yellowish portion, which is missing even in a 
rudimentary form, the glandula membran. nictitant. is enormously developed. 
Liophis merremii Wiedersheim: ‘This is another example in which no 
yellowish part is observed in the rear of the glandula labialis superior. 
Daspeltis scaber Wagler: Kathariner (1898) described in this species, 
besides other sets of oral glands, an independent poison gland, which, accord- 
ing to his judgment based upon the anatomical characteristics, can not be 
considered as a specialized part of the supralabial gland. This gland is a 
tubular, branched, and compact gland by itself and has one single central 
duct, which opens at the corner of the upper jaw in a pocket of the mucous 
membrane of a definite tooth. On the other hand, the glandula labialis 
superior is composed of numerous alveolar glands which secrete their 
product into the groove between the maxilla and the upper lip through 
