246 Miscellaneous. 



On HiTedon-metamor^ylioses ^t. By E. D, Cope. 



The late observations by various writers on the metamorphoses of 

 AmUystomct, especially those of !Mr. Tegetmeier, indicate that some 

 of the principal facts in the history- of the subject have been over- 

 looked by all of them. 



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

 Siredon, S. mex'icanus, Shaw {S. pisciformis, S. axolotl, and S. 

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

 which the Smithsonian collections contain numerous specimens. 

 Whether it undergoes a metamorphosis is entirely unknown to na- 

 tui'alists, though I would express the belief that it will be found to 

 do so occasionally, under suitable cii'cumstances. Xo Amhhjstomata 

 have been brought from Mexico south of Tamaulipas and Chihuahua 

 by any of the various naturahsts collecting for the Smithsonian 

 Institution. 



In the next place, Prof. Baird was aware of the metamorphoses of 

 all the Xorth-American species of Siredon many years before the 

 observation of it in the Jardin des Plautes, although at first he named 

 one of them Siredon liclienoid.es, treating it as a mature animal. He 

 regarded these creatures as larvte in his essay on the Xorth-American 

 Salamanders, published in Philadelphia in 184". 



Thirdly, the important observation of Dumeril * established the 

 fact that the Siredons reproduced as such ; and his account of the 

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

 positive character which we possess on that point. 



After this, in ISGTf, the writer recorded the various stages of 

 metamorphosis in difi'erent structures to be observed in reproducing 

 individuals of two species oi Amhly stoma, viz. A. tifjrinurn and A. 

 mavortium. These embraced various >S'i/'tc?o/i-characters of the 

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

 suggested that the metamorphoses observed by Dumciil Avero those 

 of A. mavortium, which was confirmed b}- an examination of speci- 

 mens sent to the writer by Prof. Dumeril a year aftcrward±. At 

 the same time the periods of metamorphosis of eight other species of 

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

 AmUystoma, whether undergoing metamorphosis or not, owing to 

 the irregularity of its occurrence in the most nearly allied species, 

 A. mavortium, or from its /S'lreJoJi-stage, ^S'. lichenoides, Baird. 



In 1868 Prof, Marsh of Yale College obser\-cd the metamorphosis 

 of the A. mavortium, confirming the conclusions of previous writers.* 

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

 and others. 



The only point remaining to be determined is whether Siredons 

 (i. e. Amhlysioma mexicanum) undergo a metamorphosis or not. 

 Among our numerous specimens I can find none that exhibit any 

 tendency toward the change. 



* Bulletin dc la Societe dAcclimatatii.n, 18Go, ii. 348. 

 t Proceedings Acad. Nat. Sciences, Pkilad. 166. 

 I Origin of Genera, 18G8, p. 47. 



