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1894.]. The Classification of Snakes. 835. 
be longitudinal (Figs. 4, 7) or transverse (Figs. 1, 2, 3, 5). In 
either of these cases they may not be spiniferous. The apex. 
or apices of the organ may be furnished with a rigid papilla 
(Fig. 5) or awn. 
In the Tortricina and Peropoda (the constrictors), the hemi- 
penis is not spinous, and the sulcus is bifurcate (Figs. 1, 2, 3), 
and in the Boidae the hemipenis is bifurcate also, although in 
some genera (Xiphosoma, Ungualia) the branches are very 
short. The external integument is never reticulate, but is 
always laminate with elongate papille at the extremities, in 
Epicrates (Fig. 2), Xiphosoma, and Ungualia. The lamin: are 
pinnate from the sulcus as an axis, in Morelia, Enygrus, Lich- 
anura and Eryx, and are transverse (flounced), in Charina 
(Fig. 3. In Ilysia they are pinnate (Fig. 1), with a few lon- 
gitudinal plicæ below. 
Similar gradations in the characters of the hemipenis are to 
be seen in the types of venomous snakes. Thus in the Pro-. 
teroglypha this organ is spinous to the tip, on a calyculate 
basis, in Hydrophis, Elaps, (surinamensis); Dendraspis. It. is 
reticulate at the extremities and spinous below, in Callophis 
(bivirgatus) ; Naja (Fig. 9); Acanthophis; Bungarus and Sepe- 
don; the apex smooth in the two genera lastnamed. In Elaps 
nigrocinctus the organ is smooth below, with spines at the 
apex. 
In Solenoglypha the genus Atractaspis is spinous to the 
apex, apparently on a longitudinally laminate basis. In the 
Viperide and Crotalidz the spines are on a flounced basis, 
The apices are calyculate in Bitis, Clotho (Fig. 10), and Vip- 
era, and spinous in Cerastes. They are calyculate in Crota- 
lide in Bothrops, Ancistrodon, Crotalophorus, Crotalus and 
Uropsophus (Fig. 11). In Crotalus (durissus ofthe Neotropical 
fauna), the papillae are not ossified; in all the other genera 
they are spinous. 
The condition of knowledge as to the lungs of snakes was 
stated by Stannius, in 1856, as follows: “The detailed ac- 
counts as to the single or double chardeter of the lungs 
leaves much to be desired. Among Ophidia Angiostomata 
there possess a single sack, Rhinophis and all Typhlopida 
