Juny 16, 1897.] 
In two minor points the list is fairly open to 
criticism, namely, in the abbreviation of authori- 
ties and references, and in the emendation of 
names. Hven those familiar with the literature 
will find difficulty in recognizing Ogilby in 
‘Og.,’ Brants in ‘Bts.,? Hemprich and Ehren- 
berg in ‘H. & E.,’ or in telling whether ‘Sm.’ 
stands for Smith or Smuts. In most cases Mr. 
Thomas has followed the original spelling of a 
name, but apparently with some hesitation, for: 
he finds it necessary to apologize for Aplodontia, 
stating that he looks ‘with loathing on these 
h-less names.’ He has, however, adopted the 
emended forms Hchinomys for Echimys, Canna- 
bateomys for Kannabateomys, Pithecochirus for 
Pithecheir, and Acodon for Akodon, although ina 
paper subsequently published he has reverted 
to the original spelling, Akodon. 
There is opportunity for much divergence of 
opinion as to the sequence and relative rank of 
the groups, for example, as to the wisdom of 
reducing the Lophiomyide to a subfamily of 
the Muride, while giving Pedetes and the 
American Poreupines full family rank. Some 
may question the removal of the Bathergine 
from the Spalacide to form a separate family 
placed after the Geomyide and Heteromyide, 
so that the Old World genera Spalax and Bathy- 
ergus, which were formerly arranged side by 
side, are now separated by two families of New 
World pouched gophers and pocket mice: 
Possibly, it may seem that the author has 
recognized a relatively large number of genera 
of Muridze, in view of the statement that all the 
recently proposed genera of Geomyide ‘‘may be 
most conveniently treated as of subgeneric 
rather than generic rank, sound as their basis 
as natural groups no doubt is.’’ 
But whatever difference there may be in re- 
gard to minor points, the fact remains that this 
paper admirably fulfills its purpose as a check 
list of genera of Rodents. 
to hope that the field haying now been cleared 
to a certain extent of nomenclatural difficulties, 
Mr. Thomas will soon undertake the work 
which has so long been neéded, namely, a com- 
plete catalogue of the Rodentia. 
T. S. PALMER. 
WASHINGTON, D. C. 
SCIENCE. 
We may venture 
107 
SOCIETIES AND ACADEMIES. 
NEW YORK ACADEMY OF SCIENCES—BIOLOGICAL 
SECTION, APRIL 5, 
PROFESSOR OSBORN moyed that a committee 
be appointed to consider and take action on the 
question of postage on natural history speci- 
mens. The chair appointed Doctors Dyar and 
Dean and Professor Stratford. Professor Bristol 
offered his resignation asSecretary. It was ac- 
cepted, and the election of his successor was 
laid over until the next meeting. 
Professor Osborn reported upon the phylogeny 
of the early Eocene Titanotheres, showing 
that they are divided into two distinct series, 
included under the genera Telmatotherium 
and Palzosyops, both of which independently 
acquired horns. The Telmatothere line begins 
with 7. boreale, a form which Cope referred to 
as Paleosyops. It is distinguished by animals 
with long narrow skulls and high stilted feet, 
and undoubtedly represented the upland types 
of the family. The Palzosyops line, as sug- 
gested by Earle and Hatcher, passes through P. 
laticeps and P. manteoceras, and leads up to 
Diplacodon, the larger species of which surpass 
in size the smaller Titanotheres of the Oligo- 
cene. The main line gives off several collaterals, 
such as P. paludosus. Lambdotherium does not 
belong in the Titanothere phylum at all. 
A second note related to a division of the two 
groups of placental mammals, the Meseutheria 
and Ceneutheria. The former, since Wortman’s 
demonstration that the Ganodonta are ancestral 
Edentates, must now embrace this division, be- 
sides the Creodonta, Lemuroidea, Tillodontia, . 
Insectivora, Amblypoda and Condylarthra. 
The third note related to the origin of the 
typical mammalian types of teeth among the 
Theriodonta, Cynodontia and Gomphodontia of 
the Triassic. It is especially noteworthy that 
the Gomphodontia afford a demonstration of the 
origin of multituberculate teeth from a trituber- 
culate ground plan, as hypothetically assumed 
by the speaker some years ago. 
Mr. Bradney B. Griffin reported that in 
Thalassema (one of the Hchiurids) the spireme 
occurs in minute ova (8 micra in diameter) 
floating in clusters in the body cavity. The 
spireme segments into one-half the somatic 
