Suborder Heterosomata 493 



has an accessory branch along the dorsal fin. The genus 

 Pleuronichthys, or frog-flounders, has the teeth in bands. Pleu- 

 ronichthys cornutus is common in Japan and three species, 

 Pleuronichthys ccenosus being the most abundant, are found 

 on the coast of California. Closely related to these is the 

 diamond-flounder, Hypsopsetta guttulata of California. Paro- 

 phrys vetulus is a small flounder of California, so abundant 

 as to have considerable economic value. Lepidopsetta bilineata, 

 larger and rougher, is almost equally common. It is similar 

 to the mud-dab (Limanda limanda} of northern Europe and 

 the rusty-dab (Limanda ferruginea) of New England. 



The plaice, Pleuronectes platessa, is the best known of the 

 European species of this type, being common in most parts 

 of Europe and valued as food. Closely related to the plaice 

 is a second species of southern Europe also of small size, Flesus 



FIG. 438. Wide mouthed Flounder, Paralichthys dentatus (L.). St. George I., Md. 



fie s us, to which the name flounder is in England especially 

 applied. The common winter flounder of New England, 

 Pseudopleuronectes americanus, is also very much like the plaice, 

 but with more uniform scales. It is an important food-fish, 

 the most abundant of the family about Cape Cod. The eel- 

 back flounder, Liopsetta putnami, also of New England, is 

 frequently seen in the markets. The males of this species 

 have scattered rough scales, while the females are smooth. 

 The great starry flounder of Alaska, Platichthys stellatus, is the 

 largest of the small-mouthed flounders and in its region the most 



