No. 494] 



NOTES AND LITERATURE 



137 



from broad to narrow, long to short, some are flat and some 

 more rounded and tapering, thick and fleshy or thin. Heads 

 vary in breadth, length, thickness, contour of muzzle, distance 

 between nares, between eyes, size of gape of mouth. Hind limbs 

 vary as to robustness or slenderness. rounded or flattened shape 

 of toes and habitual position of limb with reference to body. 

 The writer of the paper is inclined to refer most of the varia- 

 tions which he finds directly or indirectly to the nutrition of the 

 possessor. He says "excessive nutrition with these larva? seems 

 as it were to overflow into all the peripheral parts quite regard- 

 less of function." He shows very satisfactorily that the foot 

 features which seem like aquatic life adaptations are not such 

 in fact, but are due to over-nutrition. In swimming these forms 

 do not use the foot ; it lies idly alongside the body. 



The cannibal form of larva? is very interesting and wholly 

 novel. There are occasional larvae which for reasons as yet 

 unknown, and against the tendencies of most of the larvae, have 

 adopted the habit of feeding on their fellows. It was possible 

 to convert some non-cannibal larvae to the habit, while not even 

 starvation would induce others to adopt it. Cannibals, a num- 

 ber of photographs of which are shown, are characterized by 

 the great over-development of the head and under-developnicnt 

 of the body and tail. The changes came on rapidly after the 

 habit had become established, a week showing very marked 

 steps in that direction. The head enlargement includes internal 

 as well as external anatomical changes, gill arches become more 

 elongated, more numerous and much larger teeth develop in 

 the palatine region; the entire head becomes more elongated, the 

 brain more posterior in position, and, more strange still, it ' is 

 easily seen through the soft palate ... and is of a less com- 

 pact and more piscine type." All these points need fuller and 

 more detailed description and illustration than is given in the 

 paper, and will doubtless receive further attention in a later 



The paper is a valuable contribution to knowledge o tie 

 variations of Amblystoma; it does not add to the lntnvstim: 

 problem of the cause of the non-transformation of the aquatic 

 forms. We do not find ourselves in accord with the author s 

 proposition to consider this a dimorphic species having a ems- 

 trial and an aquatic form, for this seems to put the aqua IC 

 on a par with the terrestrial one. The aquatic form seems too 



