: tail of Lichanura can hardly be igned th gory = 
Pm y assigned to the one category 
_ More than to the other. eee 
course which has generally been adopted by authors; while the 
T gone So far as to unite them, An examination of the skeleton, . 
1886.] : Zoology... 293 * 
This process is shown by the following diagram (relation of the 
axis-rib to the atlas and axis): 
Capitulum. Tuberculum. | Diapophysis. |“ Parapophys.” 
g articulating with resent on the 
Teleosaurus. |“ parapoph.” of |articulating with anterior and 
. is. diapophysis | well developed | lower part of 
(hypapophysis) axis 
(hypapophysis) 
on the axis or 
` Enatliosuchus. atlas, or between 
“ se “ them 
rudimentary, 
Gav. gang. articulating with} connected by | rudimentary | present on the 
sa parapophysis rT ligament with atlas-center 
the rudim. diap. 
rudimentary, ; 
ny Paka connected by present on the 
_ Alig. mississ. \articulating with| ligament with wanting atlas-center, 
and other croc. |“ parapophysis’’|the atlas or axis, partially on the 
if present con- axis : 
nected with atlas 
ee G. Baur, Yale College Museum, New Haven, Conn, fan. 7, 
THREE PROBLEMATICAL GENERA OF MEXICAN BOÆFORM SNAKES. | 
~ Besides genera of typical Boidz known to inhabit Mexico and E 
Central America, three genera have been found whose position y 
been more or less uncertain. These are Charina Gray, Lich- 
anura Cope, and Loxocemus Cope. All of them have been re- T 
ferred by one or another author to a supposed family Erycidæ, 
_ the type of which is the genus Eryx of India and Africa. This 
family has, however, no further definition than the non-prehen- — 
sile character of its.tail; in all other respects its members agree _ 
with the Boide. This prehensile character is, however, well 
known to be extremely evanescent in snakes, and to have no | 
&reater than generic value, and sometimes not even — 
Some years ago I referred Loxocemus to the Pythonidæ, a : 
two others have been kept in the Erycida, Mr. 
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