•rphosis being suppresi 

 5 in the Menobranchus 

 opped, as in the toad i 



Development of the Reptiles. We now come to study the embry- 

 ology of those vertebrates in which there is an important embry- 

 onal membrane, the amnion, developed, besides an allantois. The 

 eggs of reptiles from their abundant supply of yolk cells, and the 

 early stages of the embryo, are so much like those of birds that 

 the reader is referred to the account of the early stages of the 

 chick for a more complete account of the early phases of embry- 

 onic life in the reptiles. 



As with birds, the eggs are enormous in size, and like those of 

 the ostrich they are laid in the sand, and are left by the parent to 

 be hatched by the warmth of the sun. 



Professor H. J. Clark, in his " Mind in Nature," tells us that of 

 all eggs those of turtles are by far the most easily preserved in a 

 healthy state during the time of incubation. "All that is required 

 to obtain them is to collect a number of turtles in early spring, 

 before May, and keep them enclosed in some shady spot where 

 they can have easy access to water and soft earth, and to feed them 

 well with fresh herbage, such as plantain-leaves, lettuce, beet- 

 leaves, etc., etc., and in the course of time, usually in May and 

 June, they may be caught, at early dawn, digging holes in the 

 earth with their hind legs, and depositing therein their brood of 

 eggs, and then covering them up." 



The lizards, snakes, and crocodiles, lay their eggs in sand or 

 light soil, the iguana in the hollows of trees, while certain lizards 

 and snakes are viviparous. Agassiz has discovered the extraor- 

 dinary fact that in turtles fecundation does not appear to be an 

 instantaneous act, resulting from one successful connection of the 

 sexes, as it is with most animals, but - a repetition of the act, thrice 

 every year, for four successive years, is necessary to determine 



