INTRODUCTION. vil 
Whittle; W. Spieden, Purser; J. R. Howison, Captain’s Clerk; F. 
Monserrat, Steward; C. Erskine, James Sheaf, S. Stearns, E. Verry, 
Seamen; J. W. W. Dyes, Taxidermist. 
The Expedition was also indebted, for many specimens of rare and 
valuable shells, to Mr. Dimond, of the Sandwich Island Mission ; 
Mrs. Richards, of the same Mission; and Mrs. Mitchill, of New South 
Wales. 
With rare exceptions, the shells were collected on the sea-beach and 
coral reefs, very few opportunities having been afforded for obtaining 
specimens from deep water, by the dredge, on account of the incessant 
employment of the men and boats on special hydrographical duties. 
Several zoological provinces not previously explored were examined, 
and furnished most interesting groups of specimens. Among them 
are the collections made at Tierra del Fuego; the land-shells of the 
Society and Samoa Islands, as well as other Pacific islands; and the 
marine shells of Oregon,—more especially those from Puget’s Sound, 
every one of which appear to be new to collections. 
In some genera the number of new species added is quite remarka- 
ble; for instance, the species added to the genus Succinea equal all 
those previously known. The genera Trochus, Perna, Avicula, and 
Mytilus have been greatly augmented. To the scanty list of naked 
mollusks previously known, additions of many new and beautiful forms 
have been made. The Cephalopods, especially, have received large 
accessions, which, for life-like colouring and delineation, have not been 
surpassed, 
My instructions were, to name and describe the new species of shells 
found in the collection, following the system of Lamarck, and, also, to 
introduce the figures of such animals as had not hitherto been pub- 
lished, or had been but imperfectly delineated, with descriptions of 
their external features. The figures were all drawn from the living 
animal, so that they are true to life as to their form and colouring,— 
more so, indeed, than any that have yet been published. The mol- 
lusks of several genera of shells, hitherto unknown, are now, for the 
first time, delineated, and are important additions to malacology. 
