Vlll 
PREFACE. 
To Mr. Hyndman, of Belfast, Mr. Thompson’s associate in 
dredging excursions and his chosen companion in working out the 
Mollusca, Articulata, and Badiata, the manuscript was also sub- 
mitted, and received many emendations and improvements which 
he alone could have supplied. 
From the scrupulous care with which every portion of the 
manuscript was thus edited and revised, I can say without hesita- 
tion that all was done that lay in our power, to bring forward 
fully and fairly the materials which Mr. Thompson had for years 
been accumulating. And yet with all of us there was a deep 
conviction that the result so attained must needs be imperfect. 
We could deal only with the materials which we found ; we could 
give only what Thompson had bequeathed. Had his life been 
spared he would doubtless have brought collateral knowledge to 
illustrate what to us was only a simple statement. He would 
have expanded what to us were merely the hurried memoranda of 
the moment, relative to some ascertained fact. He might in some 
instances have condensed and brought under comprehensive 
generalization more than one series of recorded phenomena. We 
feel, therefore, that we have claims on the consideration and in- 
dulgence of those readers who are pursuing in a truthful and 
earnest spirit the study of any department of natural science. 
The kindness and forbearance usually accorded to a posthumous 
work will not be lessened by the fact, that one of those to whom 
the publication had been intrusted did not live to complete his 
allotted task. Mr. Jas. B. Grarrett, my beloved and lamented co- 
trustee, died of fever in little more than three years after his friend 
Mr. Thompson. The painful duty then devolved on me of receiv- 
ing both his manuscripts and the originals, together with those 
memoranda which he had written for his guidance in the work he 
had so nearly completed. To Dr. Dickie I turned in this new 
emergency, and the little that remained to be done was accom- 
plished by him, with such co-operation as it was in my power to 
afford. 
Enough has been said to indicate the nature and extent of the 
as “my friend Ball,” “Mr. Ball,” “ R. Ball, Esq.,” and “Dr. Ball,” it was 
thought better to adopt the latter designation throughout, although several of the 
notes were written many years before that well-merited honour had been con- 
ferred. The same plan was adopted with regard to the names of two other 
friends, Professor E. Forbes and Professor Allman. Notes contributed by Dr. 
Ball, while these sheets were passing through the press, are indicated by the 
signature “ R. Ball.” — E d. 
