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1894.] The Classification of Snakes. 833 
previously examined. I cannot give here all the details ob- 
served, for which I refer to the papers quoted, but I give a 
general view of the results. One of these is that I am able to 
confirm the conclusion of Boulenger; i. e, that the Colubriform 
venomous snakes, the Proteroglypha, (cobras, Elapes, etc.), do 
not differ in any fundamental respect from the non-venomous 
Colubride, and that they can not be characterized as a sub- 
order. The suborders then are: 
Catodonta (Type Glauconia). 
Epanodonta (Type Typhlops). 
Tortricina (Ilysiide and Rhinophidz). 
Colubroidea (Peropoda, Asinea, and Proterogylpha). 
Solenoglypha (Typical venomous forms). 
The hemipenis is a projectile organ in the form of a hollow 
tube whose base is on one side of the middle line, and which 
opens into the anus. When retracted it lies beneath the tail, 
extending for a greater or less distance, and terminating in a 
cylindrical muscle. This has considerable length, and is 
finally inserted on a caudal vertebra. When the organ is pro- 
jected this muscle is drawn forwards, so as to evaginate the 
tubular organ. Thus the inside of the tube becomes the out- 
side, and the entire organ projects freely from its base ante- 
riorly. It finds its way into the corresponding oviduct of the 
female (Plate XXVIII, v), and when oncein place it cannot be 
tracted in most species, without invagination. This is per- 
formed by the contraction of the now internal retractor muscle. 
This is inserted on the internal face of the apex, and draws it 
inwards, so that it soon assumes the original ensheathed posi- 
tion beneath the tail It cannot be withdrawn from the 
oviduet without invagination, because it is generally set 
with strong bony spines which diverge backwards. They 
have a perfect grip on the walls of the oviduct, and would 
in some instances lacerate that organ if the two bodies 
should be forcibly drawn apart. In other cases the hemi- 
penis would be torn off at the base. Snakes sometimes partially 
project this organ, apparently in some instances for defence, 
. aS the spines are very pungent, and are sometimes curyed 
like cats claws. Such at least would seem to have been the 
