THE BATKACHIA OF NORTH AMERICA. 73 



, Measurenunts of No. 4057. 



Inches. 



Leugtli from suoiit to end of gape of moutli 55 



Length from snout to giilar fold , 1. 00 



Leugtli from snout to groin 3.50 



Length from suout to behind auus 4. 30 



Length from suout to end of tail (about) 8.55 



Length of tail (about) ., 4.25 



Depth of tail (at end vent).... 1. 95 



Width of head 1.00 



Length of fore-arm from elbow 90 



Length of hind leg from knee .' 1. 10 



Stretch of hind leg 3.40 



A specimen entirely similar, except in size and coloration, was found 

 by Dr. Horn near Beesley's Point, N. J., a well-known locality for the 

 species. The tail is remarkably thick and deep at the base, and only 

 equal from its basis to the canthus of mouth ; a groove in the dorsal 

 line behind ) tail not grooved. The color is a dark leaden brown, sprin- 

 kled everywhere with small yellow spots; spots larger on tail; belly 

 yellov^ish. Total length, (i inches and 5 lines. 



From the preceding investigation we gather that larval characters in 

 this species are in part only contemporaneous; that the branchiae are 

 lost first; the tongue develops next, and the teeth last; that the de- 

 velopment extends in older age to the lengthening of the body and tail; 

 that the progress may be arrested at a time when any degree of com- 

 bination of tliese and other features exists. That reproduction may 

 take place at any of such ditferent stages is evident from the condition 

 of development of the ova of many of the various specimens, and it 

 is known to take place in other species at earlier stages than any re- 

 corded here as adult. 



It is also to be noted that specimens from New Jersey are almost 

 always more fully developed than those from the Western regions; the 

 former is a warmer district than the latter. Of two specimens from 

 New Orleans, however, one only exhibits the dentitional characters of 

 the New Jersey individuals. The characters common to the Western 

 individuals have occasioned the opinion that it was another species, 

 which was called A. mavortium. 



Of this form I remarked in my monograph of the genus Amblystoma, 

 published in I8!J7, already referred to, that it " differs absolutely only 

 in the broader muzzle and wider separation of the outer nares. The A. 

 tigrinum retains in this case a feature characteristic of the larva of A. 

 mavortium and of all other Siredon species. The range of color vari- 

 ation is only partly different in the two, but the majority of speci- 

 mens each belong to different color types. Each occupies a different 

 geographical area, both of which are well marked in the distribution of 

 many other reptiles. Nevertheless, ultimately I think it quite possible 

 that they will have to be viewed as dcv^elopmental forms, like so many 

 other supposed species which are not sufficiently isolated from one 



