INTRODUCTION. 49 



5. Boys, in 1784, in Walker's Minute Shells, added 

 the following small species, which had before been 

 overlooked : — 



1. Valvata cristata, f. 18, 19. 



2. Helix pulchella, f. 23. 



3. Bulimns obscurus, f. 41. 



4. Achatina acicula, f. 59, 60. 



5. Carychium minimum, f. 51. 



6. Acme fusca, f. 42. 



7. Conovulus denticulatus, f. 50. 



8. Planorbis imbricatus, f. 20, 21, 



9. Segmentina lineata, f. 28. 



6. In 1786, Mr Lightfoot the botanist, in the 

 Philosophical Transactions, added — 



1 . Helix pulchella, var. crenella, t. 3. f. 1 . 4. 



2. aculeata, t. 2. f. 1. 5. 



3. Planorbis nitidus, t. 2. f. 1 . 4. 



4. Velletia lacustris, t. 3. f. 1. 



7. Dr. Pulteney, in his catalogue of the Dorsetshire 

 shells, adds — 



1. Helix caperata. 



2. umbilicata. 



3. Azeca tridens. 



4. Planorbis spirorbis. 



He added, however, to the list, at the same time, seve- 

 ral exotic species. 



8. Dr. Maton and the Rev. Mr. Racket, in 1797, 

 in the Linnean Transactions, added — 



1. Pisidium amnicum. 



D 



