xviii LIST OF ILLUSTRATIONS. 
PAGE 
Lingual dentition of Typhobia horei, Fig. 4 . . . .223 
Semi-diagram of anatomy of Typhobia horei , Fig. 5 . . . .224 
Section of otocyst of Typhobia horei , Fig. 6 . . . .225 
Part of the mantle cavity of Typhobia horei , Fig. 7 . . . .226 
Bathanalia howesi shell, Fig. 8 . . . . . .227 
Operculum of Bathanalia , Fig. 9 . . . . .227 
Lingual teeth of Bathanalia, Fig. 10 . . . . . .228 
Shell of Chytra kerkii, Fig. 1 1 . . . . . . .229 
Living animal of Chytra , Fig. 12 . . . . . . 229 
Nerves of apporrhais pes pelicani, Fig. 13. . . . . .230 
Lingual teeth of Chytra, Fig. 14 . . . . . -231 
Nerves of chytra, Fig. 15 ........ 232 
Operculum of Chytra, Fig. 16. . . . . . . *233 
Shell of Limnotrochus , Fig. 17 . . . . . . >233 
Operculum of Limnotrochus, Fig. 18a . . . . . . 233 
Lingual dentition of Limnotrochus , Fig. 18 . . . . 234 
Nerves of Limnotrochus , Fig. 19 . . . . . . -"235 
Stomach of Limnotrochus , Fig. 20 ...... 237 
Shell of Bythoceras , Fig. 21 . . . . . . . 238 
Lingual dentition of Bythoceras , Fig. 22 . . . , . . 239 
Nerves of Bythoceras, Fig. 23 . . . . . . . . 240 
Bythoceras minor shell, Fig. 24 ... 242 
Lingual dentition of Paramelania damoni, Fig. 25 . . . . 243 
Lingual dentition of Paramelania cranigranuluta, Fig. 26 . . 244 
Shell of Paramelania damoni, Fig. 27 . . . . . 242 
Shell of Tanganyicia rufofilosa. Fig. 2S . . . . . . 246 
Semi-diagram of Tanganyicia rufofilosa, Fig. 29 . . -247 
Lingual dentition of Tanganyicia rufofilosa. Fig. 30 . . . . 248 
Nerves of Tanganyicia rufofilosa, Fig. 31 . . . . . 248 
Semi-diagram of Tanganyicia rufofilosa , Fig. 32 ... 249 
Shell of Nassopsis fiana, Fig. 33 . . . . . . .250 
Semi-diagram of Nassopsis nana, Fig. 34 . . . . *. 25 1 
Animal of Nassopsis, Fig. 35 . . . . . . . -252 
Lingual dentition of Nassopsis nana, Fig. 36 . . . . . 253 
Nervous system of Nassopsis, Fig. 37 . . . . . *254 
Operculum of Nassopsis, Fig. 38 . . . . . 255 
Shell of Spekia zonata, Fig. 39 . . . . . . .256 
Lingual dentition of Spekia zonata, Fig. 40 . . . -257 
