172 



DIS(!OGLOSSlDffi. 



follows that whereas some may have spent only three 

 or four months in the water, their brothers will 

 sojourn for a whole year or more in that element. 

 Young reared by me measured, immediately after meta- 

 morphosis, from 18 to 22 mm. from snout to vent. 



Eggs. — Large, the vitellus measuring 3^ to 5 mm. in 

 diameter, varying in colour from pale straw-yellow to 

 bright yellow. They are coated with 

 Fig. 63. two transparent gelatinous envelops, 



the outer of which is tough and elastic, 

 and forms the threads by which the eggs 

 are connected in two rosary-like series 

 as they issue from the cloaca. These 

 connecting threads measure, without 

 great tension, from 4 to 7 mm., and 

 according to the number of eggs, which 

 varies between 18 and 54, the whole 

 rosary has a length of 70 cm. to 2 ra. Males observed 

 by Geisenheyner and Melsheimer with 126 and 150 

 eggs were no doubt nursing double or treble broods. 

 When fresh laid the eggs are nearly spherical, 

 but they soon acquire a more transversely oval 

 shape. Through the transparent capsules the 

 whole development can be easily followed. An 

 enormously large vitelline sac is present, and the em- 

 bryo develops uncommonly long, unpigmented gills, 

 one only on each side, with a large number of slender 

 branches along the ventral side of the trunk. These 

 gills are absorbed and replaced by internal ones, and 

 the transformations which accompany the passage from 

 the first or embryonic to the second or tadpole period 

 are all effected within the egg-capsules. The embryos 

 are at first uniform yellowish -white ; the pigment, 

 when it appears, forms two brown stripes, but before 

 hatching the little tadpole has put on his grey, 

 .more or less spotted coloration. 



Tadpole (PL I, figs. 4 and 5). — Length of body once 

 and one-third to once and a half its width, two-fifths 

 to one-half the length of the tail. Nostrils nearly 



