328 Evolution and Distribution of Fishes 



The genus Acentrophorus is primitively represented by 

 a species, A. dispersus, that was described by Fritsch from 

 the freshwater "gaskohle" of Bohemia. From the Upper 

 Permian of Durham, England, three other species have 

 been described, while Newberry referred here a lot of 

 imperfect remains, named by him A. chtcopensis from the 

 freshwater Trias of Chicopee Falls, Conn. 



The entire family, however, assumed great importance 

 and wide distribution in the Trias. Twelve species of 

 Semionotiis — all from freshwater beds — are known from 

 the lowest Triassic or Muschelkalk beds of Perledo, Italy, 

 and later from Eastern America; from the Keuper of 

 Central France and Germany; from like or possibly some- 

 what higher beds of the Upper Trias of South Africa; and 

 from Gosford, Australia. These are immediately associat- 

 ed with Aphnelepis^ Serrolepis, Cleithrolepis, Aetheolepis, 

 Pristisomus, and Colobodus, In the Australian, South Afri- 

 can, and Central German beds; with Lepidotus, Dapedius, 

 and Tetragonolepis in the Kota beds of India {2^j:2,)- 



The often abundant remains of species of Lepidotus 

 (Fig. 53) from freshwater beds of the English or conti- 

 nental Kimmeridge Clay, the Purbeck, and the Wealden : 

 the equally abundant remains of species of Dapedius (Fig. 

 27, p. 203) from the "Bucklandi" fish-reptilian strata of 

 the Lower Lias, and similar strata of the Upper Lias; as 

 well as the widely dispersed remains of Tetragonolepis, all 

 proclaim a like environal habitat, while their admixture 

 with other semionotid genera above named, give added 

 testimony. 



Fig. 53. Lepidotus minor, from Purbeck beds of Upper Jurassic 

 age, Dorset in England. One-fifth natural size. (After A. S. 

 Woodward) . 



