NO. 419.] THE ANATOMY OF AXOLOTLS. 9OI 
The gills differ from both the Colorado and the Amenia speci- 
mens. The lengths of the filament-bearing areas of three gills 
in succession, beginning with the anterior one, are respectively 
76%, 90%, and 125% of the length of the head in the Kenmare 
specimen. The corresponding figures for the Amenia specimen 
are 76%, 90%, and 117%. For the Colorado forms they are, in 
case No. 21, 33%, 50%, and 72%. In both the Dakota speci- 
mens the gills are thus noticeably much longer than is the rule 
among siredons, as hitherto reported, and among the Colorado 
specimens which are in the main in accord with the cases 
reported by Baird, Marsh, and others. The gill in the Kenmare 
specimen does not broaden distally, but is tapering from base 
to tip. This is in contrast with the Amenia specimen, where 
the gills are spatulate in form, which point may, however, prove 
to be an abnormality. The form of the gill plates in the Ken- 
mare specimen is different from either those from Colorado or 
the Amenia specimen. They are not long and filamentous as 
in the latter, and they are not short and blunt as in the former ; 
but they are wide and plate-like, tapering to the tip, the outer 
row being longer than the inner; they are arranged as in the 
Colorado forms. 
The body offers nothing for special comment. The colora- 
tion has already been mentioned, and the feet show the same 
broad foot margin of skin on the sides of the toes as is found 
in other siredons. The post-abdomen and the fin are much as 
in the Amenia form and decidedly unlike the siredons generally 
and the Colorado series. The body part is heavy and broad 
from base to tip; it is broadly convex at the tip, in marked 
contrast with the acute taper found in all the Colorado series. 
The fin is thick and strong, contrasting with the thin mem- 
branous texture of the Colorado forms, and it is not so wide 
asin them. In all of these points the post-abdomen is like 
that of the Amenia specimen. : 
An examination of the internal anatomy was made only dl 
far as it could be done by means of a short incision in the side 
Wall of the body, Through this it was possible to see the lungs 
fully developed, as in a strictly terrestrial form, and the various 
viscera were similar to those found in the St. Paul material. 
