CROCODTLIANS, LIZARDS, AND SNAKES. 701 



cated in niauy harmless suakes. The investiug tissues may or may not 

 correspond with this bifurcation. Thus the hemipenis may be more or 

 less bifurcate, Schlegel states that it is bifurcate in venomous snakes, 

 but it is not so in Hydrophis hardwiclcii, Bnnf/arus semifasciatus, lloplo- 

 cephalus coronatus, etc., while it is bifurcate in many nonvenomous 

 forms. Next to the bifurcation of the sulcus in importance, is the 

 nature of the surface of the external investment (internal when 

 retracted). In the most perfect types, both venomous and nonvenomous, 

 this surface is reticulate like tripe, the inclosed areas forming calyces, 

 which may have a suctorial function. Their borders are generally 

 papillose, and are sometimes so deeply divided into papilhe as to lose 

 their original character. These papillae may be the seat of osseous 

 deposit, becoming bristles or spines, which become larger toward the 

 middle of the length, and lose their mutual membranous connections. 

 These isolated spines may extend to the apex, but they rarely extend 

 to the base. The surface may, however, be laminate and not reticulate, 

 and the laminjc may be longitudinal or transverse. In either of these 

 cases they may not be spiniferous. The apex or apices of the organ 

 may be furnished with a rigid papilla or awn. The entire surface of the 

 organ when protruded is designed for the maintainance of its position 

 in the oviduct of the female, from which it can not be withdrawn except- 

 ing by invagination. 



In the Tortricina and Peropoda the hemipenis is not spinous, and 

 the sulcus is bifurcate, and in the Boidic the hemipenis is bifurcate 

 also, although in some genera {Xiphosoma, Ungnalia) the branches are 

 very short. The external integument is never reticulate, but is always 

 laminate with elongate papilla; at the extremities, in Uj^icrates, Xipho- 

 soma, and Ungnalia. The laminse are pinnate from the sulcus as an 

 axis in Morelia, Enygrus, Lichanura, and Eryx., and are transverse in 

 Charina. In Ilysia they are pinnate, with a few longitudinal plicse 

 below. 



The principal variations in the Colubroidea are as follows: 



No spines; surface longitudinally plicate; the surface of the hemi- 

 penis is flounced more or less transversely; the surface is more or less 

 reticulate, and the sulcus spermaticus is undivided; hypapophyses 

 anterior; the surface is reticulate or longitudinally plicate, and the 

 sulcus is divided; hypapophyses anterior; the surface is neither reticu- 

 late nor flounced, and the spines when present are disconnected; hypa- 

 pophyses continued to caudal vertebra\ 



Similar gradations in the characters of the hemipenis are to be seen 

 in the types of venomous snakes. Thus in the Proteroglypha this organ 

 is spinous to the tip, on a calyculate basis, in Hydrophis, Elaps {surina- 

 mensis), Bendraspis. It is reticulate at the extremities and spinous 

 below, in Gallophis [bivirgatus), Xaja, Acanthophis, Bungarus, and 

 Sepedon; the apex smooth in the two genera last named. In Elaps 

 nigrocinctus the organ is usually smooth, with a few spines at the apex. 



