iv INTRODUCTION. 
which the animal or coral has been mentioned since the establishment 
of the Linnzan system of nomenclature, and reference is given to the 
work in which these were first used, and especially to the different 
works treating on British animals in which it is mentioned, and also a 
reference to the best figures. The chief part of these references have 
been extracted from the admirable and classical work on the Sponges 
by Dr. George Johnston, additional references having been made to 
older exotic works which have escaped his researches, or to others 
which have appeared since his publication. 
The British Museum is fortunate in having received the chief portion 
of the specimens from the several authors who originally described the 
species, so that there can be no doubt of the specimens being the real 
representatives of the names they bear; for besides possessing some of | 
the original specimens collected and described by Colonel George Mon-. 
tague and Dr. W. E. Leach, Dr. George Johnston of Berwick has most 
kindly presented to the Museum the whole of his Collection, which he 
used in the preparation of his classical work on this subject. 
As the attention to the laws of priority, now so universally adhered 
to, has caused the alteration of a few of the names used in Dr. John- 
ston’s work, a Concordance showing the changes has been added. 
JOHN EDWARD GRAY. 
June,12th, 1848. _ 
