Suborder Heterosomata 703 
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 cenosus 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 
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Fic. 606.—Wide mouthed Flounder, Paralichthys dentatus (L.). St. George I., Md. 
flesus, 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 
