194 LAND REGIONS. 



genus Cochlost^'la has no less than 211 species. The Inilimoid 

 forms of Cochlostyla are many of them large and highly colored, 

 under a thin, hydrophanous epidermis, almost like the bloom on 

 a plum, and the bands become translucent when wetted. There 

 are 50 species (or varieties) of Melania, 38 of Neritina ; the 

 bivalves consist of Batissa, 3 ; Corbicula, 1 ; Cyrena, 3 ; Ano- 

 donta, 1. 



16. Austro-Malaysian Region, 



This division includes the islands lying between Australia and 

 the Philippines, that is to say : the Celebes, Moluccas, New 

 Ireland, New Britain, New Gruinea, and the Adniiraltj^ Louisiade 

 and Solomon Islands. 



In these islands Helix is largel}' developed ; the group Geo- 

 trochus being characteristic, although wanting in the Celebes; 

 but these islands, situated at the eastern extremity of the region, 

 have a fauna of ambiguous character, including with a number 

 of special species, many which approach those of the Philippines 

 and Malaysia. 



In the Moluccas more than 100 species are known, 28 of which 

 are operculated. In New Guinea there are 90 species, 35 of 

 which are Helices of the sections Chloritis, Planispira, Papuina, 

 and principally, Geotrochus. Leucoptychia and Perrieria are 

 peculiar genera. The Louisiade Archipelago has yielded as yet 

 but few shells; including 4 handsome species of ■ Geotrochus, 

 and a large Pupina. In the Admiralty Islands there are 44 

 species, according to Kobelt, including 25 Helices, of which 14 

 are Geotrochus. The Central Polynesian genus Partula is here 

 represented by 4 species. The 64 species of New Ireland and 

 New Britain include Geotrochus 4, Partula 2, Melania 13, 

 Neritina 16. The fauna of the Solomon Islands and New Georgia 

 is exceedingly rich : more than 160 species, have been described, 

 and the number is constantly augmenting notwithstanding the 

 difficulty of exploring countries peopled by anthropophagous 

 tribes. Heliciform shells predominate ; principally Geotrochus, 

 60 sp. ; Trochomorpha, 21 sp., and Nanina. There are a dozen 

 species of the group Placostylus (Bulimus) of which B. Gleryi 

 is the most remarkable. Relationship with the Polynesian fauna 

 is shown bj^'the occurrence of species of Partula, Diplommatina, 

 Pupina, Realia, Helicina ; with the Austro-Polynesian fauna, by 

 that of Placostylus. 



n. Australian Region. 



The Australian continent has only been partially explored for 

 shells, those of the eastern coast being best known, whilst the 

 west has so far yielded but few species — including many Bulimi. 

 In North Australia are found Helices of the group Xanthomelon, 



