Page:The Zoologist, 4th series, vol 1 (1897).djvu/118

92 pteron founded on a caterpillar? The answer would almost certainly be in the affirmative now, but posterity might reverse the verdict!

bulky volume is another instance of how science is fostered in the United States, and is the first report made by Mr. Walcott, who succeeded Mr. Powell in 1894, after that gentleman had directed the survey for thirteen years. We wish the present editor equal success and increased longevity.

With the geological contents of the volume we have nothing to do in the pages of this magazine, but zoologists may well consult and study an exhaustive memoir, by Prof. O.C. Marsh, on "The Dinosaurs of North America." As the author writes, among the many extinct animals that lived in North America in past ages, "none were more remarkable than the dinosaurian reptiles which were so abundant during Mesozoic times. This group was then represented by many and various forms, including among them the largest land animals known, and some, also, very diminutive. In shape and structure, moreover, they showed great variety, and in many other respects they were among the most wonderful creatures yet discovered."

It is stated that the best authorities now regard the dinosaurs as constituting a distinct subclass of the Reptilia, and Prof. Marsh recognizes three groups, viz. Theropoda, carnivorous forms; and Sauropoda and Predentata, both herbivorous groups. "The first of these suborders contains large dinosaurs more or less protected by a dermal covering of bony plates; the second group includes the huge horned dinosaurs; and the third is made up of the forms that in shape and structure most nearly resemble birds."

While the geological range of the Dinosauria, according to present knowledge, is confined entirely to the Mesozoic period, known so well as the Age of Reptiles, their geographical distribution was extensive. America, Europe, Asia, Africa, and Australia, have all contributed remains of these animals, but "while North America seems to have contained the greatest number of different types, some of the larger species are now known to have