20 = Mr. E. D. Cope on the Bunothertan Mammalia. 
Fig. 8 (P|. IIL). Adult. The letters 7s and cl represent the superior and 
inferior expansions of the cloaca, expansions separated at the 
level of the letter p, where the median portion (cm) of the 
cloaca comes into contact with the pharyngeal sac. The line Zz 
represents the boundary of the lateral portion of the cloaca, and 
the line / m the boundary of its median part. 
Fig. 9 (Pl. I1.). Transverse section of the filament of the posterior extre- 
mity. cell, large granular cells contained in its interior; € ¢, 
transparent cells which form its superficial covering ; f0, fibrous 
envelope ; m, section of the muscles of the aperture, which are 
produced on the ventral side nearly to the extremity of the fila- 
ment. X 150 diam. 
Fig. 10 (P1. I11.). Transverse section of the endostyle. Xx 250 diam. 
Fig. 11. Transverse section of an Anchinia at a stage a little more ad- 
vanced than fig. 7 and at the level of the stomach. x 30 diam. 
TI.—On the Mutual Relations of the Bunothertan Mammalia. 
By E. D. Copr*. 
Tue name Bunotheria was proposed by me for a series of 
Mammalia which resemble in most technical characters the 
Edentata and the Rodentia. That is, they agree with these 
orders in having small, nearly smooth, cerebral hemispheres, 
which leave the olfactory lobes and cerebellum entirely ex- 
posed, and in some instances the hemispheres do not cover 
the mesencephalum also. From the two orders in question, 
however, they are easily distinguished. ‘Their enamel-covered 
teeth separate them from the Hdentata, while the articulation 
of the lower jaw is different from that found m the Rodentia. 
It isa transverse ginglymus with a postglenoid process in 
the Bunotheria, as distinguished from the longitudinal groove, 
permitting antero-posterior motion, of the Rodentia. 
Such a group as is thus characterized will include two 
existing groups recognized as orders—the Prosimiz and the 
Insectivora. The latter group has always been a crux to 
systematists; and when we consider the skeleton alone, as 
from the standpoint of the palxontologist, the difficulty is not 
diminished. Various extinct types discovered in latter years, 
chiefly in the Eocene formations, have been additions to this 
intermediate series of forms, giving even closer relations with 
the orders already adjacent, ¢.e. the Kdentata, the Rodentia, 
the Prosimiz, and the Carnivora. As is known, the groups 
corresponding to these orders have been named respectively 
* From the ‘Proceedings of the Academy of Natural Sciences of 
Philadelphia ’ for 1883, pp. 77-88. 
