68 THE INVERTEBRATE FAUNA 
MOLLUSCA. 
This list comprises the true Mollusca only. Of the groups 
which were formerly united under the title Molluscoida, and 
which are now generally regarded as members of the exten- 
sive and somewhat heterogeneous type Vermes, the Polyzoa 
and Tunicata have already been considered; while of the 
third, the Brachiopoda, there are no living representatives in 
the Firth of Forth. 
On account of the comparatively advanced state of our 
knowledge of Molluscan faunas, and the special share of atten- 
tion which is usually given to the group by collectors, we 
have reason to believe that this is more nearly complete than 
any of our other lists. 
The nomenclature and arrangement are those given in 
Gwyn Jeffreys’ well-known work.* We have frequently, 
however, mentioned also synonyms used by Forbes and 
Hanley (“A History of the British Mollusca,” 1853), and 
other authors, especially when these were the names under 
which the species had been recorded from the Forth. 
Dr M‘Bain’s extensive catalogue+ was the foundation of 
the present list. The Mollusca of the German Expedition of 
1872, which we have already had occasion to refer to several 
times, were reported on by Metzger and Meyer,} and we are 
indebted to their work for the localities of several species, 
five of which had not previously been recorded from the 
Firth of Forth. 
Mr F. M. Balfour, F.R.S., has kindly given us a list of a 
few Mollusca which he dredged in the neighbourhood of 
Dunbar, including one of the rarest species in our list, 
Pleurophyllidia lovént. 
We desire to express our thanks to the Rev. J. M‘Murtrie, 
M.A., for much valuable assistance. He kindly revised our 
MS., and from his notes added species, localities, and remarks, 
which, coming from one with his wide knowledge of British 
shells, and experience of the conchology of the Firth of 
* «British Conchology,” by J. Gwyn Jeffreys, F.R.S. London, 1863. 
+ ‘©The East Neuk of Fife,’’ by the Rev. Walter Wood. Edinburgh, 1862. 
+ Jahresb.—VIII., Mollusca. 
