Framework 5^ 



quity of the two pairs of fins. The pelvics have moved for- 

 ward until they are under the pectorals, and the pelvis, 

 which corresponds to our hip, fastens them to the cleithrum, 

 which corresponds to our shoulder. To have your shoulders 

 resting on your hips, and the attachment of your legs almost 

 under your ears, is an ichthyologist's idea of the way to 

 change from a lower to a higher form. 



To be fair to the ichthyologist, it must be repeated that 

 when he says low he means primitive, and when he says 

 primitive he means unspecialized. The trout is so unspecial- 

 ized that it could conceivably be transformed into a land 

 animal J in fact, the earliest fossil animal which walked on 

 land had its hind legs where the trout's pelvic fins are, its 

 hips did not fasten to its backbone, any more than the trout's 

 do, and its shoulder-blades were fastened to the top of its 

 skull, just as the trout's are. Further, the trout's air-bladder, 

 which we shall consider more in detail later on, opens into 

 its throat, even as lungs do. 



The perch, on the other hand, with all its potential limbs 

 huddled against its head, and with the opening from the air- 

 bladder to the throat lost, is in a blind alley of the evolu- 

 tionary highway. It is so specialized that it can never be 

 anything but a fish, so advanced that it can never advance to 

 anything but a more advanced fish. And this holds true of 

 the bass and the tuna and the other advanced fishes, up to 

 and including those which, like the frogfish with its pelvic 

 fins up in front of its pectorals, are so advanced that even 

 the ichthyologist considers them degenerate (Figure 9). 



And it is of interest to note that while some of the fish- 

 fancier's favorites are in the advanced category, like the 

 bettas, the gouramis, the scalares, and the rest of the cichlids, 

 the majority rank lower in the scale: for characins, danios, 

 barbs, guppies, swordtails, and platies are all among the 

 more primitive fish. 



