. Animal studies. Fig. 246.—An Ostracoderm {Pterichyodes milleri), Lower Devonian of Scotland.— After Traqtjair. (The jointed appendage on the head is not a that the animals of these epochs were all of the simpler or lower kinds. For example, in the earlier stratified rocks there are no fossil remains of the backboned or vertebrate animals. When the vertebrates do appear, through several geological epochs they are fishes only, members of the low- est group of backboned animals. More than this, they represent generalized types of fishes which lack many of. Fig. 247.—An Arthrodire {Cocc&a
. Animal studies. Fig. 246.—An Ostracoderm {Pterichyodes milleri), Lower Devonian of Scotland.— After Traqtjair. (The jointed appendage on the head is not a that the animals of these epochs were all of the simpler or lower kinds. For example, in the earlier stratified rocks there are no fossil remains of the backboned or vertebrate animals. When the vertebrates do appear, through several geological epochs they are fishes only, members of the low- est group of backboned animals. More than this, they represent generalized types of fishes which lack many of. Fig. 247.—An Arthrodire {Cocc&steus decipiens), Lower Devonian of Scotland.—After Woodward. the special adaptations to marine life that modern fishes show. For this reason, they bear a greater resemblance to the earlier reptiles than do the fishes of to-day. In other words, they were a generalized type, showing the begin- nings of characters of their own and other types. It is always through generalized types that great classes of animals approach each other. 28. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Jordan, David Starr, 1851-1931; Kellogg, Vernon L. [from old catalog].
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Keywords: ., bookauthorjordanda, bookcentury1900, bookdecade1900, bookyear1903
