Chap. XI.] IMPERFECT CLASSIFICATION OF SHELLS. 387 
rich, in the marine treasures of the island have been 
filled as much by purchase as by personal exertion, there 
is an absence of the requisite confidence that all pro- 
fessing to be Singhalese have been actually captured in 
the island and its waters. 
The cabinets arranged by the native dealers, though 
professing to contain the productions of Ceylon, include 
shells which have been obtained from other islands in 
the Indian seas ; and the information contained in books, 
probably from these very circumstances, is either obscure 
or deceptive. The old writers content themselves with 
assigning to any particular shell the too-comprehensive 
habitat of " the Indian Ocean," and seldom discriminate 
between a specimen from Ceylon and one from the 
Eastern Archipelago or Hindustan. In a very few in- 
stances, Ceylon has been indicated with precision as the 
habitat of particular shells, but even here the views 
of specific essentials adopted by modern conchologists, 
and the subdivisions established in consequence, leave 
us in doubt for which of the described forms the col- 
lective locality should be retained. 
Valuable notices of Ceylon shells are to be found in 
detached papers, in periodicals, and in the scientific 
surveys of exploring voyages. The authentic facts em- 
bodied in the monographs of Eeeve, Kustek, Sowerby, 
and Kiener, have greatly enlarged our knowledge of the 
marine testacea ; and the land and fresh-water mollusca 
have been similarly illustrated by the contributions of 
Benson and Layard to the Annals of Natural History. 
The dredge has been used, but only in a few insulated 
spots along the coasts of Ceylon ; European explorers 
have been rare ; and the natives, anxious only to secure 
the showy and saleable shells of the sea, have neglected 
c c 2 
