II.— A REVIEW OF THE FLOUNDERS AND SOLES (PLEURONEC- 

 TIDiE) OF AMERICA AND EUROPE. 



By David Stark Jordan axd David Koi- Goss. 



In this paper we have tried to give the synonymy of all the genera 

 and species of flounders and soles (Pleuronectidcc) found in the waters 

 of America and Europe, together with analytical keys by which tne 

 groups may be distinguished. 



The material we have examined includes (1) all the flounders in the 

 museum of the Indiana University, which contains a large representa- 

 tion of the species found on our Pacific coast, in the Gulf of Mexico, 

 and in the Mediterranean; (2) much, but not all, of the material con- 

 tained in the United States National Museum, more especially the speci- 

 mens collected by Dr. Jordan and by Dr. Gilbert; and (3) all the floun 

 ders contained in the Museum of Comparative Zoology, at Cambridge, 

 Mass. This museum is rich in South American forms, the collections 

 made by Professor Agassiz, Dr. Steindachner, and others for this mu- 

 seum being very extensive. Only the collections in the Indiana Uni- 

 versity have been studied by the junior author; for all statements re- 

 garding other specimens, and, in general, for everything said regarding 

 the South American species, the senior author is responsible. We are 

 under special obligations to Prof. Alexander Agassiz, director of the 

 Museum of Comparative Zoology, and to Mr. Samuel Garman, curator 

 of the fishes, for many courtesies in connection with our studies in that 

 museum. 



We regard the order of Heterosomata ( u flat-fishes," with both eyes 

 on the same side of the head) as constituting a single family, Pleuro- 

 nectidcc. We find ourselves unable to separate the soles as a distinct 

 family from the flounders. The characters which mark them as a group 

 seem no more important than those which set off one subfamily of 

 flounders from another. 



The group of " Bibroniidce" recently recognized by some of the Ital- 

 ian ichthyologists as a separate family (" Bibronidi") is composed en- 

 tirely of larval forms in the early stages of their development, In this 

 condition the eyes are symmetrical and the body translucent. Several 

 generic names have been given to these peculiar forms (Peloria, Bibronia, 

 Coccolus, Charybdia, Bascanius, Belothyris), but, of course, these genera 

 can have no permanent place in the system. Peloria has been shown 

 by Dr. Emery to be the young of Platophrys (Rhomboidichthys). The 

 others seem to belong to the Cynoglossince or to some allied group, but 

 we are not yet certain as to the correct identification of any of them. 

 [1] 22b 



S. Mis. 90 15 



