32 BRAIN AND BODY OF FISH 



A comparison of the groups described above and shown in the 

 Plate with Tate Regan's Synopsis according to external charac- 

 teristics only can now be made. 



Group I. — Dorsal fin long, anal fin short. Last simple ray more 

 or less spinous or serrated. 



Carp with two barbels. 

 Crucian carp and goldfish with no barbels. 

 This corresponds with Group I according to brain pattern as 

 above. 



Group II. — Dorsal and anal fins short. 

 A. — Mouth with barbels. 



Barbel, gudgeon, and tench. 

 This compares with Group III of brain pattern. 

 B. — Mouth with no barbels, scales small. 

 Roach, rudd, chub, dace, etc. 

 These correspond with Group II of brain pattern. 



Group III. — Dorsal fin short, anal fin long Abdomen compressed 

 and forms a sharp keel over which the scales do not pass. 

 Bream and bleak. 



It is true that the bream has a brain of the carp type, but it is 

 the only fish that does not fall into line. 



This forms a fourth group from the point of view of brain 

 pattern which will shortly be described. These relations of form to 

 brain pattern are facts that are as interesting as they are remark- 

 able. The apparent discrepancies are easily explained. As regards 

 the tench we have already noticed that it has large vagal lobes, but 

 also has a large facial lobe and that the facial nerve divides on enter- 

 ing the lobe ; my original view is, therefore, probably incorrect, and 

 the tench should have been placed in Group III of brain pattern. 

 The only fish that fails to fall in with my classification is the bream. 

 Its relations to the bleak requires more research as the bleak and 

 other fish with a keel have a very unique brain pattern and are, 

 moreover, plankton-feeders. 



An examination of the brain of a Cyprinoid inhabiting the large 

 lakes of tropical Africa has furnished material wliich has enabled 

 us to describe the fourth group of Cyprinoid brain, in which it will 

 be found that the brain of the bleak can be included. In 1929, Mr. 

 Michael Graham made a report on a " Fishing Survey of the 

 Victoria Nyanza," and brought home a specimen of a Cyprinoid, 

 Engraulicypris argenteus, which he kindly placed at my disposal 

 for the purpose of an examination of its brain. An interesting 



