374 PALEOZOIC TIME — CARBONIFEROUS AGE. 



The genus Walchia, characterized by lax and very short, spreading leaves, 

 began near the close of the Carboniferous period, but is much more numerous in 

 species during the Permian. Tree-ferns of the genus Psaronim are common, as 

 in the Upper Coal measures. 



Fig. 616 A, pinnule or branchlet of a large- frond of Neur&pteris Loschii, a 

 species common also in the Coal measures; A r , a portion showing the venation. 

 Fig. 616 B, a small part of a specimen of Annularia -carinata Sternberg ; the stem 

 is jointed, as in the Equiseta, and gives off branchlets at the articulations; 

 these branchlets are also jointed, and have whorls of leaf-like appendages at the 

 articulations; in 616 B, only the first joint and its whorl are shown, of natural 

 size; in B' a branch is shown (of reduced size), consisting of its several joints 

 and whorls, but the natural termination is wanting. Fig. 616 C, Walchia piri- 

 formis Sternberg. The figures are from the work of Geinitz. and Gutbier on 

 the Permian of Saxony. 



2. Animals. 



Corals of the Cyathophyttum family, Brachiopods of the genera 

 Productus, iSpirifer, and Orthis, Cephalopods of the genera Conularia 

 and Orthoceras, and Ganoid fishes, with vertebrated or hetero- 

 cercal tails, give a Palaeozoic character to the Fauna. But there are 

 many new features : among these the most prominent is the ap- 

 pearance of Lacertian Reptiles of the tribe of Thecodonts, — species 

 having the teeth set in sockets, as the name (from the Greek) implies. 

 This transition-character is apparent also in the number of old 

 animal as well as vegetable types that here fade out, — for it is the 

 period of the last of the species of Productus, Orthis, Murchisonia; 

 the last of the extensive tribe of Cyathophylloid corals, which made 

 coral reefs far greater than those of modern seas ; nearly the last 

 of the extreme vertebrate-tailed (heterocercal) Ganoid fishes. These 

 groups had already dwindled much before the Permian period ; 

 for some prominent Carboniferous genera, as the Goniaiites, do not 

 reach into it. The old or Palaeozoic world was dying out, while 

 within it new types were coming forth, prophetic of the earth's 

 brighter future. 



Characteristic Species. 



1. Radiates. — (a.) Polyps. — Cyathophylloid Corals; also corals of the genus 

 Stenopora (Chsetetes). (b.) Echinoderms. — Crinoids of the genus Cyathocrinus, 

 a Palaeozoic genus; Echinoids of the genus Eocidaris, near the Palaeozoic 

 Archseocidari8. 



2. Mollusks. — (a.) Bryozoans. — Fenestetta retiformis, found in the Permian 

 of Russia, England, and Germany, besides a dozen other related species. 



(b.) Brachiopods. — SpWifer undulatm Sowerby, from England, Lower Zech- 

 stein in Saxony, — some specimens two and a half inches broad ; Spirifer cris- 

 tatus, from the Zechstein, Germany ; Productus horridus Sowerby, from England 



