LABYRINTHINE APPARATUS OP LABYRINTHIO PISHES. 511 



probably of a vein too) from the fourth arch to the labyrin- 

 thine apparatus (fig, 13). In certain other fishes we meet 

 with the same branches of gill-arteries. Johann Muller, in his 

 famous work on Ganoid fishes, describes the artery of the un- 

 developed extra gill as an arterial branch of the first branchial 

 arch. 1 Therefore, that the artery leads to the supplementary 

 gill-apparatus from the gill-artery is not an anatomical rarity, 

 but a consequence of the greater development of capillaries, 

 and their particular disposition in the labyrinthine apparatus. 

 If we remember that Peters proved the labyrinthine apparatus 

 to be only a part of the branchial arch irregularly developed, 

 we must, in my opinion, have expected that the labyrinthine 

 apparatus would receive its artery from the artery of its arch, 

 and that its function would be the same as that of the other 

 branchial arch, but adapted to the special wants of these semi- 

 terrestrial fishes. 



1 J. Miiller, * Ueber den Bau und die grenzen der Ganoiden und ueber das 

 natiirliche System der Fische,' Berlin, 1876. 



VOL. XXVIII, PART 4. NEW SER. M M 



