HYOBRANCHIAL APPARATUS OF SPELERPES 549 



So, with the possible exception of the suprapeduncularis, the 

 same conclusion may be drawn in regard to the hyobranchial 

 muscles as for the hyobranchial skeleton, namely, that during 

 the true metamorphic period all changes are indicated and well 

 on their way to completion, and only a continuation of the 

 process already started is necessary before the adult condition 

 is attained. 



CONCLUSIONS 



In concluding, there are three points which I wish to em- 

 phasize: 



First : that the hyobranchial apparatus of the larva is char- 

 acterized by a certain firmness and rigidity which is greatly in- 

 creased by the presence of a branchial plate. This plate is a 

 universal phenomenon among larval Salamandrids, but has been 

 generally overlooked in the past. 



Second: that the hyobranchial apparatus in the adult has 

 become very delicate and slender, and capable of a great com- 

 plexity of motion, adapted to its mode of respiration and the 

 capturing of prey. 



Third: that the transition from the larval condition to that 

 of the adult is brought about not by a mere breaking down of 

 the parts that are to be lost and the simple shifting of the posi- 

 tion of others, but by a complex process which involves the 

 degeneration and loss of certain parts through phagocytosis and 

 the formation of new tissues in the adult position. 



BIBLIOGRAPHY 



Cope, E. D. 1887 The hyoid structure in ambh'stomid Salamanders. Amer. 



Nat., vol. 21. 



1889 The Batrachia of North America. Bull. no. 34, U. S. Nat. Mus. 

 Druxer, L. 1902 Studien zur Anatomie der Urodelen. Zool. Jahrb., Bd. 15. 



1904 Zungenbein-, Kiemenbogen-, und Kehlkopfmusculatur der 



Urodelen. Zool. Jahrb., Bd. 19. 

 Duces, A. 1835 Recherches sur I'osteologie et la myologie des Batraciens. 



Mem. Savans Etrangers, 6, Paris. 

 Emerson, Ellen T. 1905 General anatomy of Typhlomolge rathbuni. Proc. 



Boston Soc. Nat. Hist., vol. 32. 

 Fischer, J. G. 1864 Anatomische Abhandlungen iiber die Perennibranchiaten 



und Derotremen. Hamburg. 



JOrRN.\L OF MORPHOLOGY, VOL. 33, NO. 2 



