1004 



CLASS PISCES. 



fore part and the head are not bilaterally symmetrical. They swim 

 with one side upwards and the other downward, the head being 

 twisted round so as to bring the two eyes upon that side which 

 becomes the upper one, and which alone is coloured. There is no 

 swim-bladder, and the dorsal and anal fins occupy almost the entire 

 length of the body. Remains of a species of Rhombus or Turbot 

 (fig. 940) are found in the Middle Eocene of Monte Bolca, and 

 those of a Solea (Sole) in the Miocene of Wiirtemberg. 



Suborder 3. Pharyngognathi. — In this small suborder a 

 portion of the rays of the dorsal, anal, and pelvic fins is formed 

 by non-articulated spines. The lower pharyngeal bones are united ; 

 and the swim-bladder has no duct. 



Family Pomacentrid^e. — Of this large family the only European 

 fossil representative is Odonteus from the Middle Eocene of Monte 

 Bolca, which is allied to the existing Heliastes ; but Professor Cope 

 thinks that Priscacara from the Eocene of North America may 

 perhaps be referable to it, although vomerine teeth are present. All 

 the members of this family have ctenoid scales. 



Family Labrid^e. — The Wrasses are a large family of littoral 

 fishes most abundant in tropical and temperate regions, and char- 

 acterised by their cycloid scales, the single dorsal fin, the thoracic 

 position of the pelvic fins, and the absence of teeth on the palate. 

 Many of them have the lips greatly thickened ; and the pharyngeal 

 bones bear molariform teeth. The existing genus Labrus is recorded 

 from the Middle Eocene of Monte Bolca and the Miocene of 

 Switzerland ; while Saurinichthys of the Miocene of France appears 

 allied to the living Odacina. Protautaga 

 of the Eocene of North America is the 

 ancestral form of the Black-fish (Tautagd) 

 of the same country. 



Family Pharyngodopilid.e. — A number 

 of extinct fishes more or less nearly allied 

 to the Wrasses, but differing in several points 

 very markedly from that family are regarded 

 as forming a group by themselves. The 

 type genus Pharyngodopilus (Numniopala- 

 tus) occurs in the French Miocene, and in 

 the Tertiary of the Canaries ; closely allied 

 to which is Phyllodus from the Cretaceous 

 of Germany and the London Clay of Shep- 

 pey, derived teeth being also found in the 

 Suffolk Crag. The pharyngeal teeth of Phyllodus (fig. 941) are 

 remarkable for their thin and leaf-like structure, and also for the 

 rapid manner in which they are succeeded from below by fresh 

 ones. The imperfectly known Egertonia from the Lower Eocene 



Fig. 941. — Pharyngeal teeth 

 of Phyllodus from the London 

 Clay. 



