2 ACHATINA. 



Type, Achatina achatina (L.). 



Distribution : Tropical Africa. Achatina extends north- 

 ward to about 7 above the equator in East Africa (Galla- 

 land), and a degree or two higher in the west (Sierra Leone). 

 Southward, the genus is roughly limited by the Tropic of 

 Capricorn, but in the east a few species descend to the lati- 

 tude of Delagoa Bay, or about 25 S. Lat. South of the 

 Tropic, most Achatinoid species now known belong to the 

 genera Cochlitoma and Metachatina. 



The EGGS of A. panthera are small and numerous. One 

 individual deposited its eggs while in my possession. I 

 counted 196. They were oval, yellow, with a thin calcar- 

 eous shell; length 6 mm. (Gibbons, J. of Conch., ii, 143). 

 In A. fidminatrix von Martens found dull pale-yellow eggs 

 measuring 6x5 mm. The size of the egg-capsule seems to 

 vary much less than that of the adult, judging from the 

 data at hand, the length of the egg being from a tenth to 

 a thirtieth that of the adult shell. 



The EPIPHBAGM of Achatina (pi. 42, fig. 8, A. panthera 

 mossambica, after Brancsik) has been described and figured 

 by Crosse (1881, A. panthera, Nossi-Be), Brancsik (1893, 

 A. mossambica) and Smith (1899, A. immaculata) . It is 

 pure white and porcellanous, lusterless out-side, but within 

 covered with a glossy film which has a pearly luster. In 

 the narrow upper portion there is a slit outside and a raised 

 ridge within, which "looks exactly as if a knife had been 

 thrust through from the outside so as to force the substance 

 out into a ridge," which may be either slightly slit along 

 the summit, or imperforate. It is about as thick as the 

 epiphragm of Helix pomatia, and is notched below to fit the 

 contour of the aperture. (See Crosse, J. de C., 1881, p. 197, 

 pi. 8, f. 2; Brancsik, Jahrcsh. Trenc. Corn., 1893, pi. 10, f. 

 2; Smith, P. Mai. Soc., iii, 309). 



Achatina is a less evolved group than Burtoa, Metachatina, 

 Cochlitoma, Archachatina, or Pseudachatina. The first two 

 have been further modified in the structure of the columella, 

 while the last four have attained a higher type of repro- 

 duction and have made more progress in sculpture-evolution, 



