2 DR. NELSON ANNANDALE ON 



The breathing apparatus of these snails is of complex 

 structure and the branchial chamber is divided into two parts, one 

 of which may be described as a lung for breathing air, -while the 

 other is a cavity in which it is supposed that oxygen can be 

 extracted from water. They are, however, practically air-breathers, 

 and may be observed t ) riss to the surface from time to time and 

 thrusb out through the surface-film a stout funnel-shaped siphon, 

 through which they draw air into their lung. 



In countries that have a dry and a wet season, the Ampul- 

 lariidae aestivate or hibernate in the former, burying themselves in 

 the ground, where they remain in a comatose condition, with the 

 operculum tightly closing the shell, until rain falls. 



The shell does not increase iu size while the animal is inac- 

 tive ; indeed, growth seems to be limited to the early part of the 

 active season. A growing shell can usually be recognized by the 

 extreme thinness of the free margin of its mouth. 



The eggs are large and have a brittle, white, calcareous shell. 

 Suue species lay them in irregular masses in depressions in the 

 ground, while others attach them to the tree-trunks, posts, etc., at 

 the edo-e of water. In the former case the eggs are spherical and 

 adhere together lightly, in the latter they may be so closely compact- 

 ed as to be irregular in form. In one Siamese species (Pachylabra 

 turbinis) only the inner eggs of the mass are fertile, the outer eggs 

 bung degenerate and forming a protective covering for the fertile 

 ones. 



Only one genus is at present recognized among the Orien- 

 tal Ampullariidae, but it will probably be necessary to separate a 

 small Indian species (Ampullaria mix Reeve) on anatomical 

 grounds. This species differs from its present congeners in living 

 in small mountain torrents. There has been much dispute within 

 the last few years as to the generic, and hence the family, name of 

 the ordinary species. Until recently all those forms the shell of 

 which has a right-handed spiral were known as Ampullarm 

 Lamarck (179!)), and the family as Ampullariidae ; the genus was 

 believed to be of circumtropical range. But there can be no doubt 

 (1) that the type-species of Ampullaria was (though Lamarck was 



JOURN. NAT. HIST. SOC. SIAM. 



