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432 Scientific Intelligence. 
and its limbs much larger and adapted for supporting the body on land. 
Archegosaurus must bave been in all respects more ichthyoid and aquatic 
than any of the species of Dendrerpeton or Hylonomus. 
The skull figured by von Meyer under the name of Sclerocephalus 
Hauseri may have belonged to an animal more nearly allied to Dendrer- 
peton than were the species of Archegosaurus. 
If the animals of the type of Archegosaurus existed in the coal period 
in Nova Scotia, their remains would not be likely to occur in such repos- 
itories as the erect trunks of Sigillariz, but only in strictly sub-aqueous 
deposits. 
V. BOTANY AND ZOOLOGY. 
ecially to our own time, and which may be designated as the school 
of immutability, denies most positively any tendency to variation in the 
vegetable kingdom. According to it, the forms of species never alter 
in the slightest degree ; and when two plants of the same genus present 
asa their own characteristics from generation to generation. 
i 
» Although the absurdity of the latter view seems evident enough, De- 
caisne proceeds to refute it, by the record of his observations and spere 
ments. He has raised seedlings from four very different varicties of 
