240 Miscellaneous. 



On ^iTQ^an-metamorplioses 6,-c. By E. D. Cope. 



The late observations by various writers on the metamorphoses of 

 Amhiijstoma, especially those of Mr. Tegetmeier, indicate that some 

 of the princij)al facts in the history of the subject have been over- 

 looked by all of them. 



In the first place, no one ha« seen any metamorphosis of true 

 Siredon, /S'. rnexicanus, Shaw (S. jnsciformls, >b'. axolotl, and 8. 

 mnculatas auctorum), which inhabits the lakes of Mexico, and of 

 M'hich the Smithsonian collections contain numerous specimens. 

 Whether it undergoes a metamorphosis is entirely unknown to na- 

 turalists, though I would exjjress the belief that it will be found to 

 do so occa.sionally, under suitable circumstances. No jimUifstornata 

 have been brought from Mexico south of Tamaulipas and Chihuahua 

 by any of the various naturalists collecting for the Smithsonian 

 Institution. 



In the next place, Prof. ]iaird was aware of the metamorphoses of 

 all the North-American species of >Siredon many years before the 

 observation of it in the Jardin des I'lantes, although at first he named 

 one of them Hlrcdon lichenoides, treating it as a mature animal. Ho 

 regarded these creatures as larva) in his essay on the North-American 

 Salamanders, ])ublislicd in rhiladelphia in J 847. 



Tliirdly, the imjjortant observation of Dumeril * established tho 

 fact that the Sir(;donH reproduced as such ; and his account of the 

 Kubscfjuent loss of larval characters by the offspring is the first of a 

 positive character wliicli wo possess on that point. 



After this, in ]8f57t, the writer recorded the various stages of 

 metamor];)hosis in different structures to bo observed in reproducing 

 individuals of two species of AmMystoma, viz. A. ti(/rinuin and A, 

 mavortimn. These embraced various »S'iV^c/on-characters of the 

 dontal, branchial, and dermal organs, and of coloration. It was 

 suggested that the metamorjjhoses oljserved by iJumeril were those 

 of A. mavortitcvi, which was confirmed by an examination of speci- 

 mens sent to the writer by Prof. Uumeril a year afterward J. At 

 tho same time the periods of metamorjihosis of eight other species of 

 the genus were stated, and tlie Mexican Axolotl was regarded as an 

 Am/ili/stoma, whether undergoing metamorpliosis or not, owing to 

 tlie irregularity of its occurrence in the most iiearly allied si)ecies, 

 A. mavortium, or from its Sired on-iitny;c, *S*. liclienoides, IJaird. 



In 18(58 Prof, Marsh of Yale College obsei'ved tlie melumor])liosi8 

 of the A. mavortium, confirming th<! conclusions of previous writers. 

 Since that time the changes have been observed by Mr. Tegetmeier 

 and others. 



The oidy point remaining to bo determined is whether Siredons 

 (i. 0. AirdAijsUmM mexicanum) undergo a metamor])liosis or not. 

 Among our numerous specimens 1 can find iione that exhibit any 

 tendency toward the cliango. 



* IJuUetin dis la Sociutd d'Accliniatation, IHCO, ii. MH. 

 t Proceedings Acad, Nat. Sciences, I'hilad. lUU. 

 \ Origin of Genera, 1808, p. 47. 



