114 



Actinoptenjgii Anacantli ini Percesoces, 8fc. 



posits, like the Miocene of Oeningen, Switzerland, and the Upper 

 Eocene of Aix in Provence, France, have also yielded species 

 of Anguilla, and some fine examples from the first-named 

 locality are preserved in the collection. 



SUB-ORDER IX. Anacanthini. 



This sub-order, which comprises the symmetrically-formed 

 Cod-fishes (Gadoidei) and the remarkably unsymmetrical Flat- 

 fishes (Pleuronectoidei) , is not known to have many representa- 

 tives in the fossil state. N"ons of the fins have spinous rays 

 (hence the name) ; the median fins are almost invariably well 

 developed; and the pelvic fins, when present, are either 

 thoracic or jugular in their position. 



Nemopteryx and Palceogadus are Gadoids from the black 

 slates of Grlaris ; other undescribed forms occur in. the London 

 Clay of Sheppey ; and a small recent Gadus is shown in a nodule 

 from Glacial Clay, Bindalen, Norway. 



The " Flat-fishes " are characterized, except in the very 

 young state, by the peculiar habit of constantly swimming and 

 resting upon one side, the fore part of the head, with both eyes, 

 becoming gradually twisted to the upper or opposite side in the 

 adult. Species equally modified or " specialized " are met with 

 even in the Eocene of Monte Bolca, where the living Rhombus 

 occurs; and there are small kinds of "Sole" (Solea) in the 

 Miocene of Ulm, Wiirtemberg ; it is remarkable, however, that 

 no less-altered ancestral types have hitherto been recognised. 



SUB-ORDER X. Percesoces. 



The Scombresocidas, Atherinidaa, Mugilidse, and Sphyrremdse 

 are not definitely known below the Upper Eocene, though 

 Rhinellus, from the Upper Chalk of Mount Lebanon and West- 

 phalia, may belong to the first family. The Atherinidse are 

 represented by Mesogaster in the Upper Eocene of Monte Bolca, 

 and the Mugilidaa (" Grey Mullets ") apparently by Mugil itself 

 in the corresponding beds of Aix in Provence. The great, 

 voracious " Barracudas " (Sphyrsenidee) of the West Indies and 

 other tropical seas, also have small representatives at MonteBolca. 



SUB-ORDER XI. Pharyngognathi. 



This is a group of spiny-finned fishes characterized by the 

 coalescence of their two lower pharyngeal bones, which support 

 a powerful dentition. 



