On Mammals from South America. 367 
Furthermore, it is difficult to understand how “ Quadrate 
bone articulating with paroccipital” can be given as a 
diagnostic character of the Ophidia, when we remember that 
the supratemporal fparoccipital, Cope] is absent in three 
families of that suborder (Typhlopide, Stenostomatide, Uro- 
peltide), where the quadrate articulates with the prootic or 
with the prootic and the exoccipital. 
In stating that ‘‘ Johannes Miiller first placed the distinc- 
tion on a sound basis by showing that in the Ophidia the 
frontal and parietal bones descend to the basicranial axis as 
in no other vertebrates,” Prof. Cope appears to ignore that 
such an arrangement is not universal in Snakes, since in 
some (e. g. Psammophis) the frontals do not descend, and are 
widely separated from the sphenoid in front of the parietals, 
which do not actually close the brain-casein front. That some 
Lacertilia agree with the Ophidia in the downward extent 
of the parietals the author himself admits; and as the teeth 
of a slow-worm are as much devoid of “ dentinal roots” as 
those of a snake, it may beasked, What remains of Prof. Cope’s 
new definition of the suborders of the Squamata ? 
L.— Descriptions of Four small Mammals from South 
America, including one belonging to the peculiar Marsupial 
. Genus “ Hyracodon,” Tomes. By OLpFIELD THomas. 
7, | 
y CE NOLESTES *, nom. nov. 
Hyracodon, Tomes, P. Z, 8. 1863, p. 50; nee Leidy, Proc. Ac. Philad. 
viii. p. 91 (1856). 
Type: C. fuliginosus, Tomes, /. c. 
Cenolestes obscurus, sp. n. 
Very much as described in C. fuliginosus, but double the 
size. 
Rather smaller than Mus rattus. Fur soft, thick and close. 
General colour uniform brown (approximately bistre-brown 
of Ridgway) all over, rather darker along the median line of 
the back; but otherwise there are no variations or markings 
* xawds, modern; Ayor7ys, a pirate or other predatory person. The 
affix “-Jestes” is connected in mammalogy with small and ancient fossil 
marsupials, e.g. Microlestes, Amphilestes, &c., so that the above name 
may be considered to represent an existing animal with ancient fossil 
relatives. The question whether this should be “ -estes’’ or “-leistes” 
has been carefully considered and submitted to classical authorities, by 
whom I am informed that as the iota subscript in Ayers would not have 
been pronounced at all, the proper transliteration is as above. 
