24 EEOGS. 



usually seeks the shallows for egg laying, although not exclusively. 

 Almost every year some egg masses are found in the middle of 

 ponds where the water is 3 feet deep or more. It tends to lay in 

 special areas (PL XVII, fig. 3), as do the wood frog and the leopard 

 frog. At one time, in an area 3 by 3 feet, 18 bunches were depos- 

 ited. In another spot of the same dimensions 31 bunches were 

 foimd. AU of these areas gave excellent illustrations of the placing 

 of bunches one upon another. The greatest number of bunches 

 observed upon one support was a case in which 7 were noted. 

 Quite frequently on one tuft of grass, or on a stick, one finds one 

 or more bunches of eggs of the spotted salamander, a bunch of 

 leopard frogs' eggs, and as many as two bunches of pickerel frogs' 

 eggs immediately above them — seldom below, because laid later. 

 At the time of deposition a bunch may be 1 to 2 inches in diameter, 

 but it soon expands to 3^ or 4 inches. It is usually firm and globu- 

 lar (PL XV, fig. 3). The egg complement of the pickex'el frog 

 may be from 2,000 to 3,000. The bright yeUow or orange lower 

 andf the brown upper halves of the eggs of the pickerel frog make 

 them the most easily distinguishable of all our true frogs' eggs. In 

 nature the eggs may hatch within 11 to 21 days. 



The green frog begins ovulation in the late spring or early summer, 

 the extreme dates being May 23 and August 10. When the air 

 temperature reaches 65 to 74°, or the temperature of the water 

 surfaces 68 to 76°, the green frog may be expected to begin breed- 

 ing. Surface temperatures are probably very influential in con- 

 trolling the breeding habit, because of the position of the eggs after 

 they are laid. When the air temperatm'e reaches 80°, the species 

 breeds commonly. Dm'ing Jime and the first part of July the eggs 

 of this form are very common ; thereafter they diminish in numbers 

 mitil the last of July or the first of August, when a few stragglers 

 deposit the last eggs of the breeding season. This species lays 

 mainly at night, but the author has twice seen it laying during the 

 day. 



The mass of the green frogs' eggs floats on the surface of the water. 

 The typical form (PL XV, fig. 2) is a diskhke film of a single 

 layer of eggs, loosely attached or free. The eggs have the upper 

 halves black and the lower halves white or creamy white. They 

 may be found in the middle of the pond, where it is filled with a 

 cover of algse at the surface, or with hornwort, water miHoil, Chara, 

 Nitella, or similar water plants, which make a mat of vegetation 

 from the bottom to the surface, or where isolated patches of grass, 

 water plantain, etc., grow in the middle of a pond. Usually, with- 

 out such conditions, the masses occur abcmt the edges of the pond 

 (PL XIII, fig. 3), attached to grass, smartweed, etc., either growing 

 in or extending into the water. In 100 or more cases hardly an 

 exception to the surface deposition has been noted, but a few appar- 

 ent exceptions have occurred. One egg complement was found m a 

 somewhat scattered mass on leaves and twigs partially submerged. 

 In another instance some of the complement was at the surface 

 and the rest in water 4 to 6 inches deep. Inasmuch as such masses 

 were found some time after deposition, a rise in the level of the 

 pond could easily have brought about this anomalous condition. 

 Another variation in the location of the egg mass is occasionally 

 recorded. The mass may be attached to grass stems, the point of 



