90 E. D. Cope on Siredon Metamorphoses. 



Thirdly, tlae 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 1867,f the writer recorded the various stages 

 of metamorphosis in different structures, to be observed in 

 reproducing individuals of two species of Amhlystoma, ra: 

 A, tigrinum and A. mavortium. These embraced various Sire- 

 don characters of the dental, branchial, and dermal organs, and 



served by Dumeril were those of A. 



firmed by an examination of specimens sent to tne writer dt 

 Prof Dumeril,:}: a year afterward. At the same time the periods 

 of metamorphosis of eight other species of the genus were 

 stated, and the Mexican axolotl was regarded, as 2iXiAmhlystm% 

 whether undergoing metamorphosis or not, owing to the irregu- 

 larity of its occurrence in the most nearly allied species, i. 

 mavortium^ or fi-om its Siredon stage, S. lichenoides Baird. 



In 1868 Prof Marsh of Yale College observed the metamor- 

 phosis of the A. mavortium^ confirming the conclusions of pre- 

 vious writers. Since that time the changes have been observed 

 by Dr. Tegetmeier and others. 



The only point remaining to be determined, is whether SiK; 

 dons (i. e. Amblystoma Mexicanum) undergo a metamorphosis 

 or not. Among our numerous specimens I can find none tliat 

 exhibit any tendency toward the change. 



I might add here that I have had for a time in a winter 

 fernery, a large New Jersey specimen of Amblystoma (igrinurii. 

 a foot in length. It is nocturnal in its habits, and remains 

 during the day in its burrow. This extends through the long 

 diameter of its prison, and has three outlets, which it keeps open. 

 From one of them, as evening approaches, it projects its head 

 and watches with attention what is transpiring in the room. 



In the same case are specimens of the common Pkthodon 

 cinereus of both varieties. During this, as in former years, 1 

 observe that this species is nocturnal, and is a great climber. 

 They will climb the rachis of a most slender fern, or spear ot 

 grass, and lie in a coil on the end of a tall frond or other nar- 

 row support, which may be sufficient to bear their weighM^ 

 a height of a foot or eighteen inches above the ground. " l^y 

 clunb a plate of glassVith great ease, by adhering closely ^ 

 its smooth surface with their moist abdomen. When disturbea 

 on some high perch among the herbage, they leap away by '^ 

 sudden unbending of the coiled body, in the manner of some 

 caterpillars. 



, 1865, II, 348. 



iedings Acad. Nat. Sciences, Philad., 

 a of Gen 



1868, p. 4 



