PINS OF GAKOIDS AND TELEOSTS. 601 



EXPLANATION OF THE PLATES. 



[Unless otherwise stated the figures are natural size.] 



Plate XXI. 



Eig. 1. Polyodon folium. Radial elements of the dorsal fin. 



2. Amia calva. Radial elements of the central portion of the dorsal fin. 



3. Lepidosfeus osseus. Radial elements of dorsal fin. 



4. Polyptencs hichir. Two radial elements, with their flnlets and spines, 



from anterior part of dorsal fin. 

 6. „ „ Two similar radial elements from posterior part of 



dorsal fin (supra-caudal fin). 



6. „ ,, Radial elements of anal fin. 



7. Osteoglossiim formosum. Five radial elements from aentral portion of 



dorsal fin, with four fin-rays. Twice natural 

 size. 



8. „ „ Four radial elements of anal fin and four fin- 



rays. Twice nat. size. 



9. Conger conger. Four radial elements of dorsal fin. 



10. „ „ Distal radial segment and its " peg-and-socket " articu- 



lation with a fin -ray. 



11. Esox lucius. Radial elements of dorsal fin and their fin-rays. 



12. Barbus vulgaris. Radial elements of dorsal fin and fin-rays. 



13. ,, „ Radial elements of aual fin and fin-rays. 



14. Platgstoma tigrimim. Radial elements of dorsal fin and their fin-rays. 



15. ,, „ Dorsal view of anterior radial elements. 



16. „ ,, Pour radial elements of anal fin. 



17. Citharinus Geoffroyi. First four radial elements of dorsal fin. 



18. ,, „ Dorsal view of first three radial elements showing 

 mode of articulation of fin-rays with distal radial segment. Twice 

 nat. size. 



Plate XXII. 



Fig. 19. Gymnotus electricus. Four radial elements of anal fin. 



20. Pleuronectes platessa. Five radial elements of dorsal fin. 



21. Holoeentrum sj)imJerosum. The first four and the last eighteeen radial 



elements of the dorsal fin. 



22. „ „ Dorsal view of four radial elements from 



anterior section of dorsal fin, to show 

 mode of formation of the " chain-link " 

 articulation and the dorsal groove. 



23. „ „ Radial elements of anal fin. 



24. Mesoprion gembra. The first four radial elements of the dorsal fin. 



25. „ „ Three radial elements from the non-spinose 

 posterior section of the dorsal fin. 



