328 MEMOIRS OF THE CARNEGIE MUSEUM. 



forked. On each side is a single postcleithrum or none. Vertebrae never fewer 

 than twenty-eight (9+19). 



Jordan and Evermann, in their Catalogue of North American Fishes, recognize 

 only the two families, Plcuronectidse and Soleida?, but in the more recent scheme of 

 Regan there is considerable further subdivision. Among fossil forms, Solea proper 

 first appears in the Lower Miocene, and a species commonly assigned to "Rhombus" 

 (in the Cuvierian sense) is present already in the Upper Eocene. The term Rhombus 

 was, however, applied in 1800 by Lacepede to a genus of Butterfishes, or seven 

 years before its employment by Cuvier for the turbot; hence modern usage requires 

 it to be replaced among flat-fishes by the term Bothus, proposed in 1810 by 

 Rafinesque. 



Not all of the characters pertaining to the recent Bothus can be observed in 



the Eocene forms, and in particular, fewer vertebrae are present in the latter, the 



number being not more than nine abdominal and nineteen caudal. Hence it is 



desirable to designate the fossil species commonly referred to "Rhombus " by a 



new generic name. The term Eobothus may be conveniently employed for this 



purpose. 



Eobothus, nom. nov. 



In general like the existing Bothus, but with not more than nine abdominal 

 and nineteen caudal vertebrae. Mouth wide, the jaws and dentition being nearly 

 equally developed on both sides; a narrow band of minute, conical teeth on the 

 margin of the jaws. Abdominal vertebrae with broad transverse processes and 

 very small, delicate ribs; epi- and hypaxial spines at base of caudal fin somewhat 

 expanded, but not fused together into laminar plates. Both pairs of fins present; 

 dorsal arising just over the eye; caudal fins separate, rounded behind. Scales 

 small and thin, showing under the lens very fine parallel, more or less longitudinal 

 or obliquely directed striae. 



4. Eobothus minimus (Agassiz). 

 (PI. XLV, Figs. 1-2). 



1796. Pleuronectes quadratulus G. S. Volta, Ittiolit. Veronese, p. 260, pi. I.XIII, 



fig. 3 {errore). 

 1835. Rhombus minimus L. Agassiz, Neues Jahrb., p. 301 (name only). 

 1839-42. Rhombus minimus L. Agassiz, Poiss. Foss., Vol. IV, p. 289, pi. XXXIV, 



fig. 1. 

 1859. Rhombus minimus A. B. Massalongo, Specimen Photogr. Anim. Foss. Agr. 



Veron., p. 36, pi. XIII, fig. 1. 



