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7G iu;lletin 'm, tnited .states natk^nal Mrsr.UM. 



tl.cir outlines more oval tlian triangular, the third and fonrtl. toes and 

 second and third lin-ers more nearly .M,nal. The develepn.ent ..( the 

 diin-rent embrvonic eonditit.ns mav be carried on ver.v nne(|nall.v in 

 dillcrent specimens, so that one cannot see the true specilie charac- 

 ters in small individuals, or even in lar-e ones in which tiiere is the 

 slij,'hfest indication of the brandiial slits or their tults. 



The same adult individual ditrcrs, too, in dillerent seasons. While 

 somesi)ecies appear to reside almost entirely in water, others do so only 

 partially. Kven the same species may pass a more aquatic lite in one year 

 than in'anodier. A more i)ersisteiit residence in water is shown l»y tlio 

 broader and more depressed (li;,'its, Iiij;herand more compressed tail, and 

 more or less decided ridjre (sometimes even membranous). I have no 

 doubt that an animal while possessinj; these Ceatiires in marked decree 

 when in the water wmild lose tlieiii to a measurable extent after ii 

 Ienj;lhened residence on land. This aijuatic habit is j,aMierally greatest 

 (hiring the breeding season. 



The preceding paragrajdi is taken from Professor liaird's maims«*ript. 

 I will further extend and illustrate the same, and add that the names. I. 

 calij'ornicnse and A. iiutvuhttum have iteeii applied by (Iray and llallowidl 

 to forms of this species. 



Various changes of form during the late metamorphosis of this ani- 

 mal have been already enumerated in the prefatory remarks on the 

 genus. A feature of diifeitMice mentioned altove -the varying length 

 of the fourth <ligit— ai)peais to be ipiite independent of other devel(»p- 

 mental conditions. In a specimen in the Mnseuin of the Philadelphia 

 Academy from Kansas, thi.s digit has but three ithalanges on both feet ; 

 in another locality three on one, four on the other foot, and tiie same 

 occurs ill No. .'{!M»4, of the National .Mnseuin. In all the other specimens 

 at my disposal they are, as in this section of the genus, \-\. 



The varieties of this species which may l)e distinguished by their 

 coloration are as follows : 



a (Californieiise.) IJlackish, with slightly i)aler belly; a series of 

 large, oval, yellow spots on lower part of side and tail (in one specimen 

 a few on each side of dorsal line). System of nuieous por«'s well (h>vel- 

 oped, especially below ramus of the Jaw on each side. From California 

 only ; eight specimens; No. lO.Sl. 



fi Brown, yellowish below; larger lateral and smaller dorsal yellow- 

 spots, irregularly arranged. Fewer miu-ous pores (»ii eaeii si<le the 

 gular region. Fourteen siiecimens ; mostly from Kansas and Nebraska, 

 one from Missouri, one from latitude ;>,So, two from New Mexico, and 

 two from Chihuahua; Nos. lOfJo, 4()i(», 3!t.o5«, 1(m;-J, |(l.S4, l!)(>S, ;5!)S|«. 

 The type of A. uehnhmnn belongs her*'. There is no material diUerencc 

 between this and the coloration of A. t'uirinum. 



y Ground brown, crossed I)y transverse yellow bands, which inoscu- 

 late more or less ou the dorsal region, so as to obscure, sometimes almost 



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