ADDENDA. 



H 



Tiie followins: notes were too lute for insertion into tbo bo'j' of the 

 liooU: 



AMIJLYSTOMA TlfiRIN'KM fJioeii. (p. HI). 



Don .Tos('' M. Velasco assorts tliat tlie Sircdtni vtcrinnnis {S. Inimhohltii) 

 iiii(l('r;fo«'s a nictaniornliosis, lint lie nowlicrc (l('S(!riI)('s tlie ailnU. He 

 tliil (»l).s('ive in 187S* the nietamorpliosis of the Amhli/stomd tiyrinum in 

 ,s|i('('ini('ns from Lake Santa Isabel, three miles north of the City of 

 >l('\i('o. It (loos not appear that he discriminates between the two 

 species, so that when he states that the S. mcxicaiiUN is found in Lake 

 /iimitiin^'o, thirty-two miles north of the ('ity of Mexico, we are not 

 ceihiin whether it may not be the .1. tijiriiium to which he refers. 



The Sirrtloii firacih's ix\n\ S. licliennides of ISaird are both larval forms of 

 tlie .1. lUjriuum. 



Dr. li. \V. Sim fold t, IJ. S. Army, thus describes the metamori)hoses 

 of the yt»H/>///s^)»m tiyrhnnii, i\n observed by him at F(Mt Wingate, N. 

 Mex. (S(Men(;e, September, l.SSr», p. 203): 



'•(1) Axolotls are more readily converted into And)lystomas if kept 

 ill wiiter containing but little air, and I'ice irrsa. 



"(L') If traiistoi'mati(Mi is forced up to a certain point in development, 

 tile reptile arrives at the higher form without any fiiitlicr iiiterferen(H\ 



"(.'i) Axolotls live in the water with apparent comfort a <'oiisiderable 

 and varying length of time after their gills have been absorbed. 



''(1) After the nietamori>liosis is eomi)leted their power to return to 

 the wa'.er again to live seems to depend upon the moult, and whether 

 they have lived in moist or dry places since the metamorphosis. 



''(."») r.y varying the conditions under which tUese animals live, we 

 <'iiii at, our ]>leasiire retard or accelerate their development to the higher 

 stiiges. 



"(<•) Young Axolotls are more easily transformed than the older speci- 

 mens, luit this rule also depends largely upon the conditions under 

 which these animals live. 



"There is another very important fac^tor that enters into this meta- 

 morphosis that, so far as the previous accounts go, is not touched 

 upon, and that is the (pu'sticm of their diet during the experiments. 

 Axolotls aie very voracious creatures and eminentlv cannvorous. 



' I<:i N.itMr:il('/ii, iv, l-TH. 



453 



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ifri 



