GENERAL OBSERVATIONS. '383 



aspect and foliage of the Pine tribe. The Cycads have the habit of 

 foliage nearly of a Palm, the vernation of a Fern, the leaf uncoiling in 

 its development, along with the wood, flowers, and fruit, and hence the 

 essential structure, of a Conifer. 



Thus it was true of many of the grand divisions that they embraced 

 a wider range of characters than belongs to the divisions which after- 

 ward appeared. In some cases, these comprehensive types occurred 

 along with the groups of which they were in a sense the combination, 

 as in the case of the Lepidodendrids with the Ferns and Pine-tribe, 

 during the Devonian and Carboniferous ages. In other cases, they 

 were prophetic of one or two groups yet to exist, as with the Ganoids, 

 which foreshadowed reptile life long before it appeared, and also the 

 purer fish type. 



3. Many of the Paleozoic species were much larger than later species 

 of the same groups. Among Crustaceans, there were Trilobites larger 

 than any living Crustacean ; species of the Eurypterus group five feet 

 long, while the nearest existing species are not an inch long ; Ostra- 

 coids of ten times the length and a thousand times the bulk of modern 

 kinds ; and so also with the Phyllopods. 



Among Insects, there were Neuropters whose wings were over three 

 inches long and two wide, vastly beyond the size of any recent May- 

 fly. Among Fishes, there were Sharks at least thirty feet long, or 

 near the size of the largest living species. Among Reptiles, the an- 

 cient Amphibians were gigantic, compared with the frogs and salaman- 

 ders of the present day ; the earliest known had its fore-foot four 

 inches broad. Among Plants, the ancient Lepidodendrids were great 

 trees ; while the modern Lycopodia, to which they are related, are two 

 feet or less in height. 



The Entomostracans (Trilobites, Phyllopods, Ostracoids, Eurypte- 

 rids, etc.) made their grandest display in the Silurian and Devonian 

 ages, and Cryptogamous plants their best in the Carboniferous age. 



4. Many of the Paleozoic species were multiplicate forms, the body 

 containing more than the normal number of divisions. In normal 

 Crustaceans, the number of segments, or rings, of which the thorax 

 and abdomen consist, is fourteen ; but, in the great majority of the 

 Paleozoic species, including all the Phyllopods and many of the Tri- 

 lobites, the number was indefinite. Again, in the Echinoids, of Post- 

 carboniferous time, the number of vertical series of plates was more 

 than twenty, the normal number. 



5. Very many of the earlier Paleozoic animals were fixed species 

 with stems or other mode of attachment, like flowers. The Crinoids are 

 examples among Echinoderms ; the Graptolites, among Acalephs ; the 

 Corals, among Polyps ; Bryozoans and Brachiopods, among Mollusks ; 



