-1892.] NEW YORK ACADEMY OF SCIENCES. 51 
the carnivorous marsupial Dasyurus, in the single instance of 
Myoxus among Rodentia, in certain Edentates, Tardigrada and 
Manidz, and notably in certain members of the carnivorous 
groups of Arctoidea. 
In taking a general view of the Carnivora, it appears that in 
respect to the structure of this portion of the alimentary tract, 
as well as in reference to other features, the Cynoidea, including 
the dogs, the wolves, jackals and foxes, form a well-marked 
~central group, with highly developed and convoluted cca, from - 
which on the one hand the Ailuroidea, including cats, civets and 
-hyenas, depart, with cecum uniformly present, but short and 
markedly pointed at the termination, suggesting the degenera- 
tion of a formerly more developed structure, while on the other 
the Arctoidea, bears, weasels and raccoons, constitute a series 
bound together by many common fundamental peculiarities of 
structure, and presenting in many members of the group a 
complete or nearly complete absence of a cecal appendage. In 
the typical Urside the absence of the czecum appears to be the 
rule. 
Among the Procyonide, Nasua has long been known to pre- 
sent the same peculiarity. The addition of Procyon lotor to 
the list of forms devoid of a cecum has, to my knowledge, not 
been made before, although the close relations existing in other 
respects between the subfamilies of Procyonine and Nasuinze 
would render the agreement in this particular not unexpected. 
As regards the remaining families of Cercoleptidze and Ailuri- 
«dee, no data are at hand. 
In the group of musteliform Arctoidea the absence of the 
cecum in Jfustela has been noted. It is among the subfamilies 
of the Mustele that further investigations should revéal inter- 
esting forms, for here in other respects deviations from the 
Arctoidean type are met with, as the transition from the planti- 
-grade Galictis to the subplantigrade Gulo and the completely 
digitigrade weasels and martens. 
Surely, the general impression gained from a bird’s-eye view 
‘of the mammalian alimentary canal, which would assign to 
herbivora a complicated cecal apparatus, and reduce the same 
to the simpler forms in Carnivora, must become modified when 
~considering the marked exceptions prevailing in the group 
under discussion, where with a combination of frugivorous and 
carnivorous habits, the ileo-colon presents this complete reduc- 
tion, nor could we desire a better illustration of the truth that 
‘other factors besides use influence and determine structural 
peculiarities. The persistence of a primitive ancestral type in 
“one, and successive modifications of the same in other directions, 
