O. C. Marsh—New Fossil Mammals. 343 
definite tessera,—and especially that no such disruption is sup- 
posable between lines that never cease to cross one another at 
an appreciable angle. The infirmity of all this, however, is 
sufficiently exposed by the inquiry how it appears that W 
will not have traversed and cut the polygonal series throughout 
us utmost capacity of extension, while yet at a limiting position 
short of M—even as C O (referring back to the figure under our 
Caption xxviii B) will have traversed and cut A B throughout 
Its utmost capacity of extension when it has reached the 
limit C R. 
This new exemplification, supplied by our author’s own labors, 
and supplementing his own history of fruitless attempts multi- 
pled on this subject, in spite of failures in the past, only affords 
hew evidence how amply any approved demonstration, now or 
hereafter, of the doctrine of parallels will be recognized and 
esteemed as having accomplished a scientific desideratum. 
Notice of some Remarkable Fossil Mammals; by O. C. MARSH. 
The Museum of Yale College has recently received the 
Temains of several fossil mammals, new to science and of 
great interest. One of these, which is represented by the entire 
around its lateral and posterior margins an enormous crest. On 
Summits are obtuse, and nearly round. They are solid, eet 
at the base, which is perforated by the upper extremity of the 
canine. Near the anterior margin of the nasals there is still 
another pair of horn cores, which are near together, and have 
obliquely compressed summits. The nasal opening was small. 
The premaxillaries are slender, and without teeth. 
The upper canines are greatly elongated, slightly curved, and 
itudi e lower portion is thin and 
