ORDERS CHIMEROIDEI AND DIPNOI. 



955 



hibits the large parasphenoid, and the anterior and posterior nares. 

 In regard to its distribution in past times, we meet with remains of 

 this genus in the Jurassic of Colorado and Montana in the United 

 States, and also in the Lower Jurassic of Stonesfield near Oxford ; 

 it is, moreover, abundant in the Upper (Keuper) and Middle (Mus- 

 chelkalk) Trias of Europe, and has been recorded from the Lower 

 division (Bunter) of that formation ; it also occurs in Illinois in 

 beds, which are thought to be probably Triassic ; while in India 

 teeth are very common in the Maleri group of the Gondwana system 

 of the Central Provinces, which is not improbably also of Triassic 

 age. Further, Professor Cope has recorded the genus from strata 

 in North America identified by him with the Permian ; but the 

 species from the European Permian originally referred to this genus 

 belongs to Ctenodns. 



Family PhaneropleuridtE. — In this family, which has been 

 placed by some in the Crossopterygian Ganoids, we still have the 



883. — Phaneroplcuron Andersoni] from the Devonian of Scotland, one-half 

 natural size, a, Scale magnified. 



continuous vertical fin, the diphycercal caudal fin, and the narrow 

 axis of the paired fins characteristic of the preceding families ; but 

 the scales are said to have a ganoidal structure, jugular plates are 

 present, and there is a series of minute teeth in the margins of the 

 jaws. This family is typically represented by Phaneropleuron (fig. 883), 

 of the Devonian and Carboniferous of Scotland and the Devonian 

 of Canada, and the allied Urone?nus of the Scottish Carboniferous. 

 We may, however, here mention the genera Megapleia-on 1 and 

 Conchopoma from the Permian of the Continent, which should prob- 

 ably find a place in this or an allied family. The former genus has 



1 The rhomboidal scales which have been described as belonging to this genus 

 are those of a Ganoid. The name should properly be Megalopleiwum. 



