CHAPTER XI 



GEOGRAPHICAL DISTRIBUTION OF LAND MOLLUSCA {continued) 



THE ETHIOPIAN, NEARCTIC, AND NEOTROPICAL REGIONS 



D. The Ethiopian Region 



The Ethiopian region includes the whole of Africa south of tlie 

 Great Desert, and Southern Arabia, together with the outlying 

 islands, excepting those of the Atlantidean province (p. 297). 



Eegarded as a whole, the Ethiopian is poorest in land Mollusca 

 of all the tropical regions. And yet its characteristics are very 

 remarkable. The entire Achatina group is peculiar, and takes, 

 especially in W. Africa, some curious forms {Golumna, Per icier is, 

 Pseudachatina). Carnivorous Mollusca {Ennea, Giblnis, etc.) are 

 highly developed, especially in the south and east, the largest 

 known helicoid form (Aerope) being from Natal. In the posses- 

 sion of these types of the Agnatha, Africa is more closely related 

 to the Australasian than to the Oriental region. The true Cyclo- 

 stoma are entirely peculiar to the region, but are absent from 

 West Africa. 



Fresh-water Mollusca are abundant and characteristic, especi- 

 ally in and near the Great Lakes. Zanistes, Cleopatra, and 

 Meladomus, among the operculates, together with Mutela and 

 Aetheria (Unionidae), Galatea and Fisclieria (Cyrenidae), are 

 peculiar. 



In its negative, as well as its positive features, the Ethiopian 

 region is markedly isolated. Helicidae and Naninidae are equally 

 deficient, the former, indeed, attaining some numerical predomin- 

 ance in the extreme south, but the species are nearly all insignifi- 

 cant in size and colouring. It is only in Madagascar that 

 Helix asserts itself. Arion, Limax, Hyalinia, Clausilia, and a 



