bufo. 225 



common frog may be regarded as tbe two European 

 types in which there is least individual divergence in 

 the breeding- time. Rollinat also reports having met 

 with an isolated breeding couple near Argenton, in 

 France, on the 18th of June, 1893. In the spring of 

 1897 I captured a pair in a pond at Anseremme, near 

 Dinant, Belgium, on April 29th, about three weeks 

 late ; the female, a large specimen, spawned the 

 following day. 



Eggs. — Small, 1^ to 2 mm. in diameter, entirely black, 

 in regular files of three or four (two when stretched), 

 in long mucilaginous strings looking like glass tubes. 



Fig. 83. 





The eggs number 4972 to 6840 according to Heron - 

 Royer's counting, 1911 to 4152 in three broods 

 counted by W. Evans. The strings measure (with 

 the eggs in double file) 9 or 10 feet, and can be 

 stretched out to a much greater length. The egg is 

 protected by a second mucilaginous envelop within 

 the string. The mucilages soon partially dissolve 

 and release the embryo, which, so to say, drops out 

 before it is able to execute any spontaneous move- 

 ments, before the appearance of the external gills and 

 with a very rudimentary tail, and becomes fixed by 

 its adhesive subcephalic apparatus to the outside of 

 the string, on which long lines of embryos may be 

 seen hanging motionless. 



Tadpole (PI. II, fig. 3). — Length of body about 

 once and a half its width, and three-fifths to two- 

 thirds the length of the tail. Nostrils much nearer 

 the eyes than the end of the snout. Eyes on the 



Q 



