17. PLETJRONECTES. 439 



value aa in other Pleuronectidae, we should be obliged to establish a 

 genus for almost every species, and to separate fishes which evi- 

 dently form one natural group. Thus, for instance, the lateral line 

 is strongly curved in PI. hilineatus, and but slightly in the species 

 nearest allied to it, viz. in PI. digrammus. However, in order to 

 show the limits assigned to the different subgeneric groups by their 

 authors, we shall add the names to the several sections, so far as is 

 consistent with the plan of division proposed by ourselves in the fol- 

 lowing synopsis : — 



I. Teeth compressed, truncate or lanceolate. 



A. Dorsal rays less than 90. 



a. Lateral line simple, straight or with a slight curve anteriorly. 



* Scales minute : Platessa, part., Gottsche; Pkuronectes, part.,Blkr., 



p. 440. 



1. PI. platessa. 3. PI. latus. 4. PI. franklinii. 



2. PI. pseudoflesus. 5. PI. dvinensis. 



* Scales imbricate : Pseudopleuronectes, Bllrr., p. 443. 



6. PI. americanus. 



* Scales none, skin with numerous tubeMes : Platichthys, part., 



Girard, p. 443. 



7. PI. stellatus, 



h. Lateral line with a dorsal branch : Pleuronichthys, part., Girard, 

 p. 444. 



8. PI. hilineatus. 9. PL digrammus. 10. PI. guttulatus. 



c. Lateral line simple, with a strong curve above the pectoral : Li- 

 manda, Gottscne, p. 446. 



11. PI. limanda. 12. PL ferrugineus. 



B. Dorsal rays 90 or more. 



a. A prominent spine before the anal fin : Microstomus, Gottsche ; 



Brachyprosopon, Blkr., p. 447. 



13. PL microcephalus. 



b. No prominent spine before the anal fin : Glyptocephaltis, Gottsche, 



p. 449. 



14. PL cynoglossus. 15. PL elongatus. 



n. Teeth conical. 



A. Lateral line with a veiy slight curve anteriorly. 



a. Scales very small : Platessa, part., Gottsche ; Pkuronectes, part., 

 Blkr., p. 450. 



16. PL flesus. 17. PL luscus. 18. PL italicus. 



6. Scales none, skin with numerous tubercles : Clidodertna, Blkr., p.453. 



19. PL asperrimus. 



B. Lateral line with a strong curve anteriorly : Platichthys, part., 



Girard, p. 463. 



20. PL variegatus. 21. PL umbrosus. 22. 1 . asper. 



