Nuptial excrescences on the inner metacarpal tubercle and on the inner fingers of the male are common; they reach their greatest development in the Himalayan _R. liebigi_, the male of which is "remarkable for the extreme thickness of its arms, the inner sides of which are studded with small conical black spines, each supported on a rounded base produced by a swelling of the skin. A large patch of similar spines exists on each side of the breast."[113] Specific glandular complexes in the skin are mostly restricted to a pair of lateral or dorso-lateral folds; they are often absent, but a few species, e.g. _R. glandulosa_ of Borneo, _R. temporalis_ of Ceylon, _R. elegans_ and _R. albolabris_ of West Africa, have a pair of large flat glands at the base or inner side of the arms. All the species of _Rana_, except those in the Solomon Islands, spawn in the water, where the development of the tadpoles takes its course. Those of some Indian species, notably _R. alticola_ and _R. afghana_ of the Himalayas, and _R. curtipes_ of Malabar, are very peculiar, being provided on either side of the shoulders with a large oval parotoid-like gland, well defined and crowded with pores; _R. alticola_ possesses in addition an unpaired, sharply {251}marked glandular complex on the top of the root of the tail, or rather upon the future coccyx. These complexes gradually disappear with age. The genus _Rana_, with about 140 species and subspecies, is distributed over the whole of Arctogaea so far as this is available for Amphibian life, while there are only a few stragglers in Notogaea, namely, a few species in Ecuador and in the Peruvian or Upper Amazon district. None exist in the rest of the Neotropical region, including the Antilles, and practically none in Australia; but _R. arfaki_ and _R. papua_ inhabit New Guinea and the northern corner of Australia, _R. kreffti_ the Solomon Islands. A few species are restricted to Madagascar, and a few others live there and on the continent of Africa. So far as number of species is concerned, the home of the genus _Rana_ is the Palaeotropical region; about one dozen (some of them with a very wide range) live in the Palaearctic sub-region, scarcely more in the Nearctic sub-region, and a few in Central America.