98 MANUAL OF THE MOLLUSCA. 



The species found at the Cape, Algoa Bay, Natal, &c., are foi 

 the most part different — Potamides decollatiis, Clionclla sinuafUy 

 and an Assiminea inhabit brackish "waters. 



Limax 4 



Arion..,, 1 



■Vitiina 4 



Helix 35 



Succinea 4 



Buliinus 13 



Pupa 6 



Achatina 7 



Cyclostoma 6 Aui'icula 6 



5. Yemen — Madagascak. 



The S. W. Highlands of Ai-abia (Yemen) form a distinct 

 Botanical province isolated by rainless deserts to the north. 

 The land snails consist of a few species of Helix and Bidimus, 

 Gydostoina lithidion, and 3 species of the section Otojmma, a 

 group also found in Madagascar. Two species are common to 

 the island of Socotra (No. 30), which also has a species (of Fiijm) 

 common to Madagascar. Bidimus guillaini, Cydostoma gratum, 

 modestum and Soulei/eti are found on the island of Abd-el-Gouri. 



Yery few land shells have been collected on the mainland of 

 Eastern Africa, although it is a rainy region, and well wooded 

 in the southern part ; o species only are recorded from Moga- 

 doxa and Ibu, belonging to the genera Helix, Btdimidus, Acha- 

 tina, PujKf, and Otojjoma. On the Island of Zanzibar are found 

 Achatina Rodatzi and allisa, Cydostoma Creplini and Zangite- 

 larica ; Pupa cerea is common to Zanzibar and Madagascar. 



Madagascar itself is rich in land shells ; Dr. Pfeiffer enume- 

 rates — Helix 28 sp., Bidimus 6, Succinea 14, Pupa 1, Achatina 4 

 (one of which, eximia, is allied to A. Columna, of W. Africa), 

 and 32 Cydostomidce, chiefly of the section with spiral ridges 

 {^Tropidophora), 3 of the division Oiopoma. Cydostoma carini- 

 ferum and Cuvieri are found on the Island of Nosse Be ; Helix 

 guillaini on S. Maria I. Amongst the fresh-water shells are 

 Melania amarula, Mdanatria fiuminea, and Neritina corona. 



The land shells of the Mascarene Islands are nearly all jdocu- 

 liar; we are indebted to Mr. W. H. Benson for most of the 

 information existing in respect to them. 



Comoro Islands, 



Helix russeola and Achatina simpularia are found in Mayotte ; 

 Cydostoma pyrostoma in Mayotte and Madagascar. 



