[39] FLOUNDERS AND SOLES. 263 



Type: Rhombus ocellatus Agassiz. 



This well-marked genus is widely diffused ki the warm seas. The 

 sexual differences are greater than usual among flounders, and the dif- 

 ferent sexes have often been taken for different species. As a rule, in 

 the males the pectoral fin of the left side is much prolonged, the inter- 

 orbital area is much widened and very concave, and there are some 

 tubercles about the snout and lower eye. The young fishes, as is usually 

 the case, resemble the adult females. This genus has been generally 

 called Rhomboidichthys, but the appropriate name, Platophrys, is earlier 

 as Bleeker has already noticed. 



Lately Dr. Emery has shown that the larval flounder, known as Peloria 

 heckeli, is in all probability the young of Pleuronectes podas. 



The generic name Coccolus, based on forms slightly more mature than 

 those called Peloria, probably belongs here also. 



We have seen no larval forms so young as those which have been 

 described as Peloria heckeli. We have, however, examined small trans- 

 parent flounders, one with the eyes quite symmetrical, taken in the Gulf 

 Stream, and another with the eyes on the left side, taken at Key West. 

 Both these may be larvse of Platophrys ocellatus. The figures published 

 by Emery seem to make it almost certain that the corresponding Euro- 

 pean forms belong to P. podas, although some doubt as to this is ex- 

 pressed by Facciola. 



The species of Platophrys are widely distributed through the warm 

 seas, no tropical waters being wholly without them. The group called 

 Engyprosopon seems to be worthy of generic distinction from Platophrys, 

 as its scales are large and rough ctenoid. All the known species of 

 Engyprosopon are Asiatic. 



All the species of Platophrys are extremely closely related and can 

 be distinguished with difficulty. On the other hand the variations due 

 to differences of age and sex are greater than in any other of our 

 genera. 



A species apparently belonging to Platophrys has been scantily de- 

 scribed by Schneider (Systemalchthyologia, 1801, 156) under the name 

 of Pleuronectes surinamensis. His types were small, smooth individu- 

 als ("exampla satis parva et glabra"), with the fins scaly, the mouth 

 small, the lateral line arched in front, and the dorsal rays 96, the anal 

 rays 55. These may be the young of any of the West Indian species, 

 possibly of P. lunatus or ocellatus. 



The following analysis of the species of Platophrys will doubtless be 

 found to be very unsatisfactory. There are certainly three species (podas, 

 maculifer, and lunatus) which are known to be distinct in their adult 

 state. The young forms of maculifer and lunatus are not well known, 

 nor is it known how they differ from ocellatus, spinosus, and other species 

 which presumably reach a smaller size. Only a thorough study of the 

 species, in all stages of development, in their native waters can give us 

 the characters by which the species cfcn be really discriminated. 



