TABULAR SCHEME. 73 



This tabulation does not include the slugs, which can be sorted 

 out as follows : 



Breathing hole near front of shield Geomalacus, 246. 

 Breathing hole half way along shield Arion, 241-245. 

 Breathing hole near back of shield 



Shield shagreened Amalia, 232, 233. 



Shield concentrically wrinkled Limax, 234-240. 



No breathing hole Onchidium, 318. 



The shell-bearing opisthobranchs also require a table to them- 

 selves, the nudibranchs and other sea-slugs being sufficiently sorted 

 out in the systematic chapters further on. 



Shell convolute 



Spire exposed Tornatinus, 551-557. 

 Spire hidden Cylichna, 560-564. 



Shell incompletely convolute 



Pyriform, spirally striated Scaphander, 558, 559. 

 Tumid, thin Accra, 568. 



Oval 



Spirally striated Action, 550. 

 Spire involute Bulla, 565-567. 



Ear-shaped 



Thin and white Philine, 569-576. 

 Thin, broad, horny, and glossy Aplysia, 577-579. 

 Thin, broad, and iridescent Pleurobranchus, 580, 581. 



