750 



THE THEORY OF TRANSFORMATIONS 



[CH. 



which we had inscribed Polyjprioyi. The very curious fish Anti- 

 gonia capros, an oceanic relative of our own "boar-fish," conforms 

 closely to the peculiar deformation represented in Fig. 380. 



Fig. 381 is a common, typical Diodon or porcupine-fish, and in 

 Fig. 382 I have deformed its vertical co-ordinates into a system 





Fig. 377. Polyprion. 



Fig, 378. PseudopriacantJms alius. 



Fig. 379. Scorpaena sp. 



Fig. 380. Antigonia capros. 



of concentric circles, and its horizontal co-ordinates into a system 

 of curves which, approximately and provisionally, are made to 

 resemble a system of hyperbolas*. The old outline, transferred 



* The co-ordinate system of Fig. 382 is somewhat different from that which 

 I drew and published in my former paper. It is not unlikely that further 

 investigation wiU further simpUfy the comparison, and shew it to involve a still 

 more symmetrical system. 



