96 The Wood-frog, Rana sylvaiica LeConte. 



oviposition, however, came March 28 and 29, and all these hatched in 

 11 or 12 days, April 9. The range of maximum air-temperatures was 



43 to 80 degrees, average 66 degrees; water-surfaces 52 to 68 degrees, 

 average 61 degrees; water-bottoms 48 to 64 degrees, average 59 degrees; 

 range of maximum water-temperatures 67 to 80 degrees, average 73; 

 minimum water-temperatures 50 to 71 degrees, average 61. 



In 1911 the eggs hatched in 17 days in the spring-fed pond, where the 

 maximum water-temperatures averaged 54 degrees, the minimum 44 

 degrees, the surface 50 degrees, and water-bottom 48 degrees. In 

 another pond (under an average maximum of 57 degrees, minimum 



44 degrees, water-surface 53 degrees, water-bottom 51 degrees) they 

 hatched in 13 days. Finally, in the second pond above, a maximum 

 average of 63 degrees, minimum of 51 degrees, water-surface of 55 

 degrees, water-bottom of 54 degrees, brought the ova to hatching in 

 13 days. In the first pond (under a minimum of 48 degrees, the sur- 

 face 54 degrees, bottom 50 degrees) the eggs hatched in 14 days. 



It would appear that with average water-temperatures of 44 to 50 de- 

 grees the eggs usually hatch in 24 to 17 days; with temperature of 50 

 to 60, in 17 to 7 days; with temperatures of 60 to 70, in 7 to 4| days. 



THE MATURE TADPOLE. 



Length of body 1.5 to 2.2 in length of tail, average 1.8. Width of 

 body in its own length 1.3 to 1.58, average 1.41. Nostril equidistant 

 from eye and end of snout. Eye equidistant (sometimes nearer the 

 snout) from spiracle and from snout. Distance between nostrils in 

 interorbital space 1.7 to 2.9, average 2.5, seldom under 2.0; in mouth 

 1.1 to 1.9, average 1.72. Spiracle sinistral, 1.5 to 2.0 nearer base of 

 hind legs than snout, average 1.73, rarely reaching 2.0 or under 1.7. 

 Anus dextral. Depth of tail in its own length 1.9 to 3.1, average 2.5. 

 Depth of muscular part of tail in depth of tail 1.75 to 2.8, average 2.47, 

 rarely below 2. Mouth contained 1.36 to 2 times in interorbital space, 

 average 1.62. Greatest length 47.2 mm. Greatest length of body 17.2 

 mm. Greatest length of tail 33 mm. Greatest depth of tail 13.8 mm. 



Coloration of body (Plate ix, Fig. 1 j.) : Background of back and sides 

 greenish black marked with fine gold and with a few orange spots; also 

 with iridescent areas, particularly on the sides, giving the whole a dark 

 greenish-brown appearance. A cream line extends along the upper jaw. 

 The venter has a cream ground; belly slightly pigmented at the sides; 

 gill region quite heavily pigmented, but overlaid with silver spots; 

 throat region a lavender gray with fine dark and silver spots ; the whole 

 venter iridescent, giving the belly a distinct pinkish bronze appearance. 

 Iris of eye bronze. Tail somewhat lighter than body, the pigment 

 graded evenly over the muscular portion and crests, but as a whole 

 darker above; small gold spots are scattered over the surface, some 

 of which become iridescent. 



