EEE eee See, RM ee ee ee ee OT RT nr Oe eee ae Ree a A ere 
Eee oe ers eee eo 

1891.] Cretaceous Mammalia. ` 607 
—They do not resemble 
oO the teeth of any known 
mammal, although de- 
-y A {9a scribed as having two 
FIG. ie), Be ag, aa nitor ; b, fangs, which are, how- 
Platacodon nanus. After Marsh. Types. ever, not shown in the 
figures. The premolar associated is distinctly mammalian. 
22. Platacodon nanus (Pl. vii., Figs. 4-12). The types are 
compared to the molars of Chrysochloris—They do not bear 
the most remote resemblance to the molars of Chrysochloris or 
any other known mammal. Prof. Dames considers that they 
belong to the Cyprinoid fishes.* 
The above types do not resemble in the most remote degree 
the molars in either the Multituberculate or Trituberculate series, 
—the only two mammalian series hitherto represented in all the 
discoveries of Mesozoic or Eocene times. Nor have they, as 
figured, any of the characteristics which we expect to find in 
mammalian teeth.'® They should, therefore, be considered either 
reptilian or icthyopsidan; we cannot agree with the author that 
they are “evidently mammalian.” 
The above analysis may be summarized under the following 
heads. We find that the author has: 1. Separated parts which evi- 
dently belong together; vide, various teeth of Cimolomys and 
Meniscoéssus ; 2. United parts which apparently or certainly belong 
together ; vzde, the large upper incisors with Cimolomys, the 
reptilian or fish molar of Stagodon with a mammalian premolar, 
the reptilian tooth as an upper incisor of Dipriodon ; 3. Associated 
or identified reptilian or icthyopsidan teeth as mammalian; vide, 
Platacodon, Stagodon, and incisor of D. robustus. 
The large Cretaceous fauna described by the writer is therefore 
seen to be principally composed of synonyms. We must elimi- 
nate: 
14 This author reaches eae similar conclusions in regard to this paper. Neues Jahr. f. 
Min. u. Geol., 1890, pp. 14 
15 See H, G. Seeley. " On the Nature and Limits of Reptilian Character in Mammalian 
Teeth.” Proc. Roy. Soc., April 4th, 1888, p. 129. 
