_a._ The male, distinguished by a greater development of the fore-limbs, which are armed with temporary excrescences, clasps the female in the axillary region with the fore-limbs: _Triton waltli_. _b._ The male, distinguished by a greater development of the hind-limbs and a prehensile tail, clasps the female in the lumbar and caudal regions: The _Euproctus_-group of newts: _Triton asper_, _T. rusconii_, and _T. montanus_. The act of fecundation of most of the other kinds of Urodela, notably _Cryptobranchus_, _Amphiuma_, _Proteus_, has not yet been observed. Embracing of the two sexes is the universal rule with the Anura, the male creeping on to the back of the female and clasping her firmly with the arms and hands either in the inguinal region, higher up, or under the armpits. See the numerous statements in the systematic part. This often extremely forcible, pressing embrace seems to be necessary, although the females can deposit the eggs without the help of the male, but in such cases the expulsion takes place at irregular intervals instead of at one time. When the eggs appear at last, and this happens in many species many hours, or even some days, after the beginning of the embrace, the male voids the contents of its seminal vesicles over them. Fertilisation is consequently external, with the possible exception of _Pipa_, _q.v._ p. 152. DEPOSITION OF THE EGGS AND NURSING HABITS.–The majority of the Amphibia are oviparous, but some Apoda and Urodela are viviparous. It is unnecessary to call the latter condition ovo-viviparous, since this is really a distinction without a difference. Viviparous forms:–amongst Urodela; _Salamandra maculosa_, the young burst the egg-membrane in the act of being born, and are provided with long gills; _S. atra_, the young undergo their whole development and metamorphosis within the uterus (see p. 119); _Spelerpes fuscus_, the young are likewise born in the perfect condition: amongst Apoda; _Typhlonectes compressicauda_ and _Dermophis thomensis_. The oviparous Apoda, at least _Ichthyophis_ and _Hypogeophis_, and a few of the Urodela, as _Desmognathus_ and _Amphiuma_, take care of their eggs by coiling themselves around them in a hole underground. Nursing habits are very common amongst the Anura. {56}Boulenger[28] has summarised the various conditions concerning the deposition and care that is taken of the eggs, in the following list, in which more recent discoveries have been interpolated. I. The ovum is small, and the larva leaves it in a comparatively early embryonic condition. A. The eggs are laid in the water:– _a._ Without further care or preparations: probably the majority of Anura; all European forms, except _Alytes_. _b._ The eggs are laid in a specially walled-in part of the pond: _Hyla faber_. B. The eggs are deposited out of the water:–