INTRODUCTION. 
Vll 
and Lieutenant (now Commander) Belcher, for their attention to the 
collection and preservation of the specimens, as it is chiefly owing’ to 
their assiduity that the collection has been so far extended.* 
I wish I could with sincerity have included with the above-mentioned 
names that of Mr. J. E. Gray, who undertook to describe the shells, 
but the publication has suffered so much by delay in consequence of his 
having been connected with it, that it is a matter of the greatest regret 
to me that I ever acceded to his offer to engage in it. This delay has 
from various causes been extended over a period of eight years, and 
I cannot with justice or propriety conceal from the government, the 
collectors, and especially from the contributors to the work, whose 
MSS. have been so long printed, that it has been occasioned entirely 
by Mr. Gray’s failing to furnish his part in spite of every intercession 
from myself and others : promising his MS. from time to time, and thereby 
keeping the department in his own hands, yet always disappointing 
the printer, until at length, from other causes, the publisher (Mr. Richter) 
fell into difficulties, and all the plates and letterpress were sold by the 
assignees and lost to the government. 
* Since this part of the Introduction was written, science has been deprived of two of its 
valuable members in Mr. E. T. Bennett, a gentleman whose talents are too well known to need 
any eulogium, and Mr. Collie, by whose death science has been deprived of an able and 
assiduous collector, and the service of a skilful, humane, and experienced surgeon. 
