158 



indicated by a blue spot, when they are near the surface. There 

 is an accumulation of them near the base of the tail, and they are 

 scattered more or less through the fin and tail. 



Prof. Hubbard also remarked upon two instances of ex- 

 traordinary elongation and distortion of the incisor teeth of 

 the woodchuck, which had lately come under his observation. 



In one case the incisors are deflected to the right, and pass 

 downwards, backwards and upwards, so that the vertex of that of 

 the right side is in a line with the zygoma, and rises above it, 

 while that of the left side has entered the maxillary bone of the 

 right side a little in advance of the molar teeth, and under the 

 infra-orbital foramen which it has displaced upwards, and pene- 

 trated to the lower part of the alveolus of the right incisor, over- 

 lapping its base about one fourth of an inch. The vertex of each 

 is somewhat chisel-shaped, but with the cutting edge on the in- 

 side. The left incisor only is considerably worn upon its left 

 side near the insertion into the jaw, as if by friction against the 

 incisor of the lower jaw. The righi incisor measures about 4 

 inches in length on its curve ; diameter of the spiral, |^ inch ; ex- 

 tent, 1 circle and half an inch ; length of alveolar portion, 1-^^ inch ; 

 vertex, f inch, to the right of the median line of the roof of the 

 mouth. The left incisor is only f inch distant from the same 

 line. The resemblance of the two teeth is very great in every 

 respect, though the left one, having a long insertion at each end, 

 is immovable. 



In the second case, the lower jaw was wanting, but the teeth 

 were said by the owner to "curve back by the sides of the head, 

 like the tusks of an elephant." The left upper incisor was broken 

 off near the jaw. That of the right side curves to the left in a 

 circular spiral of f inch diameter, backwards and upwards, and 

 penetrates the roof of the mouth, on the inside of the first left 

 molar tooth, into the left nasal passage ; then passes forward, 

 downward and outward, crossing under and just behind the left 

 incisor, into the mouth again. The same spiral is continued, 

 though in a smaller curve, and reaches almost to the first left 

 molar again, making in the whole extent almost two complete 

 circles. The tooth tapers regularly from the base upwards, and 



