PREFACE. 1X 
to afford a fair idea of the facts (to those who care to 
analyse them) regarding the relations of our marine 
molluscan fauna to. that of the surrounding countries. 
The short synonymy appended to each species has unfor- 
tunately been drawn up in a hap-hazard manner, the neces- 
sity for a systematic method not having been recognised 
until too late. An asterisk has been prefixed to such shells 
as have been found in our Scottish post-tertiary deposits ; my 
authority on this subject is solely the recently published 
“ Catalogue of the Western Scottish Fossils” (Glasgow, 1876), 
which I accepted as a standard, presuming it to be brought 
up to the present level of knowledge, and thoroughly purged 
of every doubtful species, or such as had not been verified 
by competent judges. It is apparent, however, that in this 
particular the haste with which the book was compiled will 
tell against its usefulness, and that the pages devoted to the 
post-tertiary mollusca will require revision. I have adhered 
to the arrangement and nomenclature adopted by Mr. Jeff- 
reys in his British Conchology, with a few trifling alterations 
of orthography or authority. 
An appendix will be found at page 113, containing the 
species recorded in former lists but not included by me; the 
number, after suppressing synonyms, amounts to no less than 
sixty-three species, but of these we may safely dismiss all, 
except some eight or nine—the remainder resting upon 
authority too slight to be entitled to much respect; indeed 
it is now time that the unsupported records of Smith and 
that of the species which are here catalogued from the Firth of Clyde only 
sixteen certainly extended their range to the north-western (Pacific) coasts 
of America, viz. :— 
Lima subauriculata, Axinus flexuosus, 
Mytilus edulis, Mya truncata, 
Mytilus modiolus, Pholas erispata, 
Modiolaria marmorata, Trochus helicinus, 
Leda minuta, Lacuna vincta, 
Laszea rubra, Velutina levigata, 
Kellia suborbicularis, Triforis perversa, 
Lucina borealis, Cerithiopsis tubercularis, 
besides these three others are doubtfully present, viz.:—Nucula tenuis, 
Fusus antiquus, and Cylichna cylindracea. 
