Miscellaneous. 303 



largest and best species ; the little spring and meadow 

 frogs only grow to 3 and 4 inches, length of body, 

 while the bullfrog reaches nine. The little "pickerel 

 frog" (Rana palustris) with bright yellow on thighs 

 and legs, has a disagreeable odor and is rarely eaten ; 

 all the others are good. We have four other species, 

 all small except the bullfrog, besides the arboreal frogs, 

 which are usually called "tree toads." 



A GREAT TRANSFORMATION. 



The change from a tadpole to a perfect frog is as 

 wonderful as the change from a hairy, crawling cater- 

 piller into a beautiful butterfly ; but somehow this won- 

 derful transformation into a frog, while well known 

 to a few, has not seemed to impress the general mind, 

 as in the case of the butterfly. What happens is this : 

 The frog lays its eggs, which are fertilized after being 

 laid, as in the case of most fishes ; the eggs are globu- 

 lar, jelly-like masses, which swell greatly after extru- 

 sion. In a few days the embryo is seen moving about, 

 and it emerges from the mass without absorbing it, 

 a most unusual waste in animal life. The young is 

 coiled in the egg, with a tail, much like an embryo 

 fish, but having its gills outside, and so hatches in an 

 almost shapeless form. Gradually it takes on the form 

 of the large proteus (Necturus), called "lizard" on the 

 Great Lakes, which retains its outside gills when adult. 

 Then these outside gills absorb or develop inwardly, 

 and the future frog is in all respects a fish. It has a 

 long embryonic fin that is eel-like, and begins back 

 of the head and goes around the slim tail to the vent. 

 Its eve is well developed, and the "herring bone" mus- 



