FKOGS. 31 



black, and usually marked with aggregate spots or blotches some- 

 what like the green-frog tadpole. In the pickerel-frog and leopard- 

 frog tadpoles, in spite of the coppery irid!escence on the belly, the 

 elongate intestine shows through the skin, wliile in the green-frog 

 tadpole the deep cream color mdes the view of the intestine. The 

 pickerel-frog tadpoles never reach 3 inches in length. (See PL XX, 



fig- 6.) 



The green-frog tadpole requires one year for growth before it 

 becomes a small fully formed frog. The same factors operate for this 

 extension of time as in the case of the bullfrog tadpole. The tadpole 

 of the green frog, however, has to attain a size slightly more tnan 

 one-half that of the mature bullfrog tadpole, and the larval or tadpole 

 period is, therefore, one-half as long. The distinctive marks are: 

 Tail greenish, mottled with brown; belly deep cream oolor with very 

 little or no iridescence; no round black spots; never over 3^ inches 

 in length. (See PI. XX, figs. 5 and 7.) 



The bullfrog tadpole requires two years or more for growth be- 

 fore it transforms or becomes a frog in form. This long period of 

 development results from several causes, among which are these: 

 The eggs are relatively small an<l are laid late in the season; and 

 the larviP or tadpoles are hatched in an immature state and have 

 to grow to a comparatively largo size before they change into small 

 bidlfrogs; that is, the mature l)ullfrog tadpole may be three times 

 as lon^ as a wood-frog tadpole or twice tliat of a pickerel-frog or 

 leopard-frog ta<lpole. Any tadpole over 3^ indies in length will 

 j)rove to bo that of a bullfrog. The distinctive marks are: Belly of 

 a straw or maize yellow color; the body and the tiiil (except the 

 lower crest of fin) with regidar round black spots; and fine yellow 

 dots all over the body. (See PI. XX, fi^s. 1, 2, and 3.) 



Possible Spfxies. — With the exception of the toad, the tadpoles 

 of soveralpossible forms are not well enough kno\\'n to describe posi- 

 tively. The toad tadpoles seldom reach more than from 1 to 1^ 

 inches in length. The small size required enables tho tadpole to 

 develop quickly into the toad form. The period of dcvelojiment 

 from the egg to transformation is from 50 to 6.5 days; from tho natch- 

 in^ to transformation, 41 to GO days. The distinctive marks of the 

 tadpole are: Body very <lark or black (not OTcenish) in appearance; 

 crests of the tail cloudy transparent or milky translucent and not 

 high; tail tip often more or less rounded. (See PI. XX, fig. 1 1.) 



The tadpole of the wood frog develops in one season; usually the 

 l)eriod of aeveloj^ment from the eggs to transformation extends over 

 about 90 days, though the range may be from 61 to 115 days. The 

 tadpole period and breeding time of the wood frog coincide with 

 those of the leopard frog. The tadpole of the wood frog never 

 becomes more than 2 inches long. Like that of the leopard frog tho 

 bellv of the wood frog has a bronzy i^d(^scence, but it is more pinkish 

 in the latter along the upper-jaw region, while the wood-frog tadpole 

 has a cream-colored line; finally, the mouth of the tadpole of the 

 woovl frog has three rows of te(>th on the upper jaw and four rows on 

 tho lower jaw, while all tho desirable species have two rows of teeth 

 on the upper jaw and three on the lower. (See PI. XX, fig. 10.) 



TJndesihable Species. —Some of the more frecpient tadpoles 

 whif.h should be avoided are those of tlu^ narrow-niouthccl toa(l, the 

 tree toad, the peeper, the swamp cricket frog, and tho cricket frog. 



