REPRODUCTION 207 



ance with the abbreviated development, caudal crests do not exist 

 and the branchial aperture closes up as soon as the gills disap- 

 pear; these are very similar to those of Ichthyophis, except 

 that there are only two functional ones on each side, the third 

 being quite rudimentary. The number of eggs in each brood 

 varies between six and thirty. In the larger H. rostratus, the 

 diameter of the egg varies between seven and eight millimetres, 

 whilst in H. alternans it varies between four and five. 



Siphonops annulatus, in Brazil, also lays its eggs on land, 

 even in very dry localities, and nurses them in the same 

 manner as the Ccecilian mentioned above. They are only six 

 in number and measure ten by eight and a half millimetres, 

 when in an advanced state of development. The embryo has 

 three large fringed external gills on each side. 



Very little is known of the habits of Typhlonectes compressi- 

 canda of the Guianas and Venezuela, one of the largest Cce- 

 cilians, reaching a length of 500 millimetres, but it appears to 

 be more aquatic than most of its relatives. A female, found in 

 the water, contained six advanced embryos of very large size, 

 one of them being 157 millimetres long. These embryos 

 breathe by means of two large flap-like membranous, external 

 gills on each side, closely connected with each other. 



Dermophis thomensis, from the island of San Thome, Gulf 

 of Guinea, is also viviparous, but appears to approach more 

 nearly to the type of Salamandra atra. In the single gravid 

 example examined, one uterus contained one young and the 

 other two, and these young had neither gills nor gill-clefts, and 

 but for size resembled the parent, except that the head was 

 more distinct from the body, and the posterior part of the body 

 was rather strongly compressed, as if for the purpose of swim- 

 ming. These young measured about forty millimetres, the 

 adult measuring up to 260. 



These are the principal examples of the various modes of 

 nursing and development with which we are at present ac- 

 quainted in the three Orders into which living Batrachians are 

 divided. But Nature does not easily reveal her secrets, and 

 many are the surprises in store for future observers. 



An inspection of the oviducts of many frogs and salamanders 

 preserved in collections suffices to show that ova with large 

 vitellus are the rule rather than the exception among those 



