x INTRODUCTION: 
form—is here omitted, as it has been shown to have no claim to 
a place in the British list, into which it had been introduced on 
the strength of museum specimens. 
Fishes.—It is fortunate—so far as the classification and 
nomenclature are concerned—that the list of British Fishes can be 
based upon reliable and satisfactory authority. The classification 
adopted is that promulgated by Dr. Giinther in his recently pub- 
lished ‘ Introduction to the Study of Fishes’; while his well-known. 
‘Catalogue of Fishes’ furnishes a safe guide to the nomenclature. 
Dr. Day’s papers in the Linnean Society’s Journal, and more 
particularly his comprehensive work on the ‘Fishes of Great 
Britain and Ireland,’ have also served as a guide to some of the 
conclusions arrived at. 
The British Fishes here enumerated are substantially those of 
the third edition of Yarrell’s ‘ History of British Fishes’ (1859), 
modified by the assistance of the writings of the two distinguished 
ichthyologists just referred to. Some few, however, of the species 
included by Yarrell, and a considerable number of those added 
by Couch, have—since the date of their writings—proved to be 
either monstrosities, varietal or immature forms of other species, 
or to have been admitted into the British fauna on insufficient 
evidence. Their omission consequently requires no further 
explanation. 
In attempting to define the faunistic position of fish, not only 
is there found a deficiency of the requisite information for the 
Yorkshire coast, but considerable dissatisfaction is the usual 
result of a reference to the works of Yarrell and Couch. 
Admirable as they are in certain respects, the vagueness of 
some of the statements made, and the want of system in the 
arrangement of the subject-matter, often renders it extremely 
difficult to ascertain the geographical range of a species, still more 
so to learn its true position in the British fauna. This remark 
applies even in the case of some of the commonest forms. It is 
true that the habits of fishes are very obscure and their natural 
