1864.] DR. J. E. GRAY ON THE URSID&. 677 
inhabiting the island of Raiatea. S. pudorina, Gld., we also con- 
sider a doubtful species. The markings and colours of the animal, 
as described by Dr. Gould, are somewhat similar to those of S. hu- 
merosa ; and we can select specimens, which are undoubtedly the S. 
humerosa, which correspond with the shell. We add a description 
of the following new species :— 
SucciNEA CosTULosA, Pse. 
T. ovata, tenui, flavide cornea, longitudinaliter irregulariter cos- 
tulosa ; anfr. iil., anfractu ultimo interdum superne obsolete 
rotundatim angulato ; apertura ovata, columella arcuata, sub- 
plicata. 
Long. 7, diam. 5 mill. 
6. A Revision or THE GENERA AND SPECIES OF URsINnE ANI- 
MALS (URSIDZ), FOUNDED ON THE COLLECTION IN THE 
British Museum. By Dr. J. E. Gray, F.R.S. 
The family of Bears (Urside) are characterized among the Carni- 
vora by having the three hinder upper grinders (that is to say, the 
hinder false grinder, the flesh-tooth, and the tubercular tooth) very 
similar in form ; they are broad and strongly tubercular. The three 
hinder teeth in the lower jaw are similar, but they are narrower and 
more elongate. 
They form a very natural group, consisting only of a limited number 
of species. The species require particular study, as they are very 
similar externally ; and the skull and teeth, which are very similar 
in many of the specimens, appear to be liable to a considerable 
amount of variation in specimens from the same locality, and with 
the same habits. 
The examination of the bones and especially the skulls of the Ur- 
side shows still further than the study of the bones of the Viverride 
the necessity of great caution in depending on the study of osteo- 
logical specimens for the distinction of species. The fact that M. 
de Blainville considers the Californian Grisly Bear, after a very 
careful study and comparison of its bones, to be only a variety of the 
common European Bear, shows how a most experienced and ac- 
curate osteologist may be misled by placing tco much confidence in 
a single branch of study. If such a naturalist may be so misled by 
the study of the bones of recent animals, how much more caution is 
required in giving any opinion or forming any theory on the study 
of fossil specimens of bones, where the determination of the osteo- 
logist cannot be verified by the examination of other parts of the 
animal in its perfect state ! 
The species of Ursidz are distributed over Europe, Asia, Africa, 
and America, and they are generally inhabitants of the mountainous 
regions of these countries. One species is marine, and common to 
the Arctic parts of Europe, Asia, and America. 
