Pleuronectes fiesus, the Common Flounder. Ossicles at base of dorsal 

 and anal fins. Scales rougli along lateral line, elsewhere rudimentary. 



Pleuronectes limanda. Shape rhomboidal; snout pointed. Lateral 

 line with a small semicircular curve anteriorly. 



III. Mouth rather small, and not terminal, but curved down to the ventral 

 edge ; teeth present only on the lower side. 



1 . Solea. The shape oval, outline of the snout regularly semicircular. Scales 

 ctenoid. Lateral line straight, but with an anterior dorsal curve on 

 the head. Tactile filaments on the lower side of the snout. Paired 

 fins may be rudimentary or absent. The dorsal eye anterior to the 

 lower. 



Solea vulgaris, the Common Sole. Pectorals on both sides of con- 

 siderable size ; nostrils on the two sides similar ; filaments of the under 

 side of the snout closely crowded together not forming any pattern. 

 Markings of the upper side consisting of longitudinal series of black 

 blotches on a yellowish-brown ground. 



Solea lascaris, the French Sole or Sand Sole. Differs from the 

 preceding in two characters — viz., the anterior nostril on the lower side 

 is dilated and fringed internally ; each of the black blotches of the 

 preceding species is represented by a number of small black specks. 



Solea variegata, the Thick-back. Nostrils on both sides similar ; 

 pectoral and pelvic fins rudimentary ; filaments of the lower side of the 

 snout connected at their bases by membranes which surround square 

 depressions. Mouth more terminal and less curved than in the other 

 species. Markings consist of five transverse dark bands. 



Solea lutea. Resembles the preceding in other respects, but has the 

 mouth much curved, the dorsal fin commencing on the extreme 

 anterior end of the snout. The markings consist of dark blotches 

 arranged as in >S. vulgaris, but there is in addition a thin black line 

 along every fifth or sixth ray in the dorsal and anal fins 



Solea Greenii, a new species just defined by Dr. Gunther, has the 

 scales, fin rays, and filaments of the left side of the head as in vulgaris, 

 but rudimentary pectorals. 



Plates I to VII, which exhibit with great accuracy the natural apj^earance of the 

 fish, will illustrate the distinguishing external features of the four commoner British 

 species of sole. But although the above-mentioned characters are those which 

 principally distinguish the species from one another, they do not exactly resemble one 

 another in every other respect. We may proceed to study their characters in greater 



c 



