344 Evolution and Distribution of Fishes 



were evolving; the former — and structurally less specialized 

 — appearing in late Triassic or in Liassic time; the latter 

 — and more evolved — from the Kimmeridgean upward. 

 The genera Leptolepis, Lycoptera, Aethalion, and Thris- 

 sops make up the former; Oligopleiiriis, Oenoscopiis, and 

 Spathiuriis the latter. 



The first of these easily became the dominant genus 

 through a long period. For remains of Leptolepis — often 

 in great abundance — occur in Upper Liassic strata across 

 the whole of Central Europe. But it is in Purbeck beds 

 that they seem to have swarmed. Thus Brodie, in referring 

 to the closely allied forms Leptolepis nanus, L. brodiei, 

 Ceramurus macrocephalus and a Pholidophorus, associates 

 them with insects, freshwater molluscs, and other fresh- 

 water fishes like Lepidotus already discussed. He also 

 describes the shoals of Leptolepis that seem often to have 

 been entombed. 



But as an excellent illustration of mixed-up records de 

 Lapparent gives from beds near Mazenay ((5/: 1 141-42) 

 Leptolepis constrictiis, and L. affinis (both synonyms of the 

 common central European L. hronni) , along with Lioceras 

 serpentimis, Inoceramiis cinctus, Belemnites, etc. He some- 

 what corrects this statement, though NOT the false im- 

 pression formed, by tabulating the beds in exact succession 

 thus : 



(5) Schists with Belemnites tripartitus and Inoce- 

 rami. 



(4) Schists and calcareous rocks with Lioceras 

 serpentinus and Belemnites grandis. 



(3) Fish-limestone with Ptychodiis, Leptolepis, 

 Cephenoplosus, {P achy cor inns) and Lepi- 

 dotus. 



(2) "Feuillet a Posidonia Bronni." 



( I ) Passage beds with Monotis stibstriata. 



Further comment on the above is unnecessary, though 

 Sauvage repeats {244:12) the admixture. His observa- 

 tions on the Leptolepidae and allies however are suggestive. 



But the most graphic references to Leptolepis are by 

 A, S. Woodward, in describing the fish-fauna of the Aus- 



