Zoology. 259 
simply substituted my names Prototheria for the Ornithodelphia or 
Monotremes, and Eutheria for the Monodelphia or Placentalia, 
introducing a new term—Metatheria—for the Didelphia or Mar- 
supialia. I perfectly concur with the belief that in these senses 
the terms are unnecessary. But far different was my use of the 
terms in question, and they were the expressions of a higher gene- 
ralization. Almost universally the placental. mammals had been 
contrasted with the non-placental. In my “Arrangement of the 
Families of Mammals” (1872), however, I combined (pp. 45, 46) 
the Placentals and Marsupials in one category (I.) with the Mono- 
tremes, in another (II.) fortifying the contrast by numerous ana- 
tomical characters; for these two sections I proposed the names 
EuTHERIA (I.) and Prororuerta (IL) in the table of 
“Contents” (pp. v., vi.) of the Arrangement. Subsequently, in 
“Johnson’s New Universal Cyclopedia” (vol. iii., 1877, p. 262), 
in the long article “Mammals,” I adopted the terms in connection 
with the definitions. It was then prevised that “the chief modifi- 
cations of the class of Mammals are expressed in three types whic 
have been differentiated as sub-classes, viz., Monodelphia, Didel- 
phia, and Ornithodelphia; these are themselves opposable under 
two categories, EUTHERIA and PROTOTHERIA.” Immediately fol- 
lowing, the groups so named were defined at length. | 
In the sense in which the terms Eutheria and Prototheria were 
used by myself I consider them to be necessary as the ver 
expressions of the generalizations formulated, but as used by Pro- 
fessor Huxley the names are simple synonyms of others long before 
in general use, and consequently “ unnecessary.” — Theodore Gill. 
THE MULTITUBERCULATA Monorremes.—It is announced in 
Nature (Feb. 16, 1888, p. 383) that Mr. E. B. Poulton has dis- 
covered teeth in sections of the jaws of a young Ornithorhynchus 
anatinus, made by Professor W. N. Parker. Three have been 
found in the upper jaw and two in the lower (the ramus imperfect), 
In the regions covered by the corneous bodies of the adult. The 
anterior tooth of the maxilla is “long, narrow and simple, as com- 
pared with the others.” The other teeth “were broad and large, 
those of the upper jaw containing two chief cusps in the inner side 
of the crown, and three or four small cusps on the outer side, while 
arrangement was reversed in the lower jaw.” 
18 observation is of the highest importance. The description 
pen like that of the dentition of the Plagiaulacid genus Ptilodus. 
renders it extremely probable that the Multituberculata are Monotre- 
mata, and not Marsupialia, as has been supposed.—E. D. Cope. 
ZOOLOGICAL Nores.—Prorozoa.—Dr. D. S. Kellicott describes 
Q C figures five new species of American Infusoria in the Microsc 
dis p. 226). They are Podophrya inclinata, P. flexilis, Carchesium 
ulatum, and Opercularia humilis. 
