AMPHIBIA. 121 



but in Amblystoma punctatum (Clark, No. 98), the male deposits 

 the semen in the water. The eggs are laid by the Anura in 

 masses or strings. By Newts they are deposited singly in the 

 angle of a bent blade of grass or leaf of a water-plant, and by 

 Amblystoma punctatum in masses containing from four eggs to 

 two hundred. Salamandra atra and Salamandra maculosa are 

 viviparous. The period of gestation for the latter species lasts a 

 whole year. 



A good many exceptions to the above general statements have been 

 recorded 1 . 



In Notodelphis ovipara the eggs are transported (by the male?) into a 

 peculiar dorsal pouch of the skin of the female, which has an anterior 

 opening, but is continued backwards into a pair of diverticula. The eggs 

 are very large, and in this pouch, which they enormously distend, they under- 

 go their development. A more or less similar pouch is found in Nototrema 

 marsupiatum. 



In the Surinam toad (Pipa dorsigera) the eggs are placed by the male on 

 the back of the female. A peculiar pocket of skin becomes developed round 

 each egg, the open end of which is covered by a gelatinous operculum. The 

 larvae are hatched, and actually undergo their metamorphosis, in these 

 pockets. The female during this period lives in water. Pipa Americana (if 

 specifically distinct from P. dorsigera) presents nearly the same peculiarities. 

 The female of a tree frog of Ceylon (Polypedates reticulatus) carries the eggs 

 attached to the abdomen. 



Rhinoderma Darwinii 2 behaves like some of the Siluroid fishes, in that 

 the male carries the eggs during their development in an enormously 

 developed laryngeal pouch. 



Some Anura do not lay their eggs in water. Chiromantis Guineensis 

 attaches them to the leaves of trees ; and Cystignathus mystacius lays them 

 in holes near ponds, which may become filled with water after heavy rains. 



The eggs of Hylodes Martinicensis are laid under dead leaves in moist 

 situations. 



Formation of the layers. 



Anura. The formation of the germinal layers has so far 

 only been studied in some Anura and in the Newt. The 

 following description applies to the Anura, and I have called 



1 For a summary of these and the literature of the subject vide "Amphibia," by 

 C. K. Hoffmann, in Bronn's Classen ^^nd Ordnungen d. Thier-reichs. 



2 Vide Spengel, " Die Fortpflanzung des Rhinoderma Darwinii." Zeit. f. wiss. 

 Zool., Bd. XXIX., 1877. This paper contains a translation of a note by Jiminez de la 

 Espada on the development of the species. 



