234 THE HISTORY OF CREATION. 
many (at Degerloch, near Stuttgart, in 1847), later also in 
England (at Frome), in 1858. Similar teeth have lately 
been found also in the North American Trias,and have been 
described as Dromatherium sylvestre. These remarkable 
teeth, from the characteristic form of which we can 
conclude that they belonged to an insectivorous mammal, 
are the only remains of mammals as yet found in the older 
secondary strata, namely, in the Trias. It is possible, 
however, that besides these many of the other mammalian 
teeth found in the Jura and Chalk systems, which are still 
generally ascribed to Marsupials, in reality belong to Cloacal 
Animals. This cannot be decided with certainty owing to 
the absence of the characteristic soft parts. In any ease, 
numerous Monotrema, with well-developed teeth and cloaca, 
must have preceded the advent of Marsupial animals. 
The designation, “ Cloacal animals” (Monotrema), has 
been given to the Ornithodelphia on account of the cloaca 
which distinguishes them from all other Mammals; but 
which on the other hand makes them agree with Birds, 
Reptiles, and Amphibia, in fact, with the lower Vertebrata. 
The formation of the cloaca consists in the last portion of 
the intestinal canal receiving the mouth of the urogenital 
apparatus, that is, the united urinary and genital organs, 
whereas in all other Mammals (Didelphia as well Mono- 
delphia) these organs have an opening distinct from that 
of the rectum. However, in these latter also the cloaca 
formation exists during the first period of their embryonal 
life, and the separation of the two openings takes place only 
at a later date (m:man about the twelfth week of develop- 
ment). The Cloacal animals have also been called “ Forked 
animals,” because the collar-bones, by means of the breast 
