LM. BIC.” MEMOfm=s 
No. I. ASCIDIA 
[Reprinted by arrangement with L.M.B.C.] 
EDITOR’S PREFACE. 
THE Liverpool Marine Biology Committee was constituted 
in 1886, with the object of investigating the Fauna and 
Flora of the Irish Sea. 
The dredging, trawling, and other collecting expeditions 
organised by the Committee have been carried on inter- 
mittently since that time, and a considerable amount 
of material, both published and unpublished, has been 
accumulated. Thirteen Annual Reports of the Committee 
and four volumes dealing with the ‘“‘ Fauna and Flora” 
have been issued. At an early stage of the investigations 
it became evident that a Biological Station or Laboratory 
on the sea-shore nearer the usual collecting grounds than - 
Liverpool would be a material assistance in the work. 
Consequently the Committee, in 1887, established the 
Puffin Island Biological Station on the North Coast of 
Anglesey, and later on, in 1892, moved to the more 
comimodious and convenient Station at Port Erin in the 
centre of the rich collecting grounds of the south end of 
the Isle of Man. | 
In our twelve years experience of a Biological Station 
(five years at Puffin Island and seven at Port Erin), where 
College students and young amateurs formed a large 
proportion of the workers, the want has been constantly 
felt of a series of detailed descriptions of the structure 
of certain common typical animals and plants, chosen 
as representatives of their groups, and dealt with by 
specialists. The same want has probably been felt in other 
similar institutions and in many College laboratories, 
