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On SHALLOW WATEK FAUNAS. 

 By a. Milnes Marshall, M.A., M.D., D.Sc, F.R.S., 



BEYER PROFESSOR OF ZOOLOGY IN OWENS COLLEGE. 



Animals may be classed according to their habitat as 

 terrestrial or aquatic, and the latter subdivided into fresh 

 water forms and marine forms. The marine fauna, again, 

 falls very naturally into three main groups, — the shallow water 

 and shore animals, the deep-sea animals, and the pelagic or 

 oceanic animals. 



The entire animal kingdom may thus be divided into 

 five groups ; and, although it is impossible to separate these 

 by sharp boundary lines, and an animal may in the early 

 stages of its existence belong to one group, and when adult 

 to another, yet the division is very generally accepted as a 

 real and natural one, and it is both possible and profitable to 

 enquire into the general characters of the several groups, 

 and to attempt to determine their mutual relations. 



I have chosen shallow water animals as the subject of" the 

 present paper, because it is with these that the Liverpool 

 Marine Biology Committee will be chiefly concerned ; and 

 I propose to confine myself to the general characters of the 

 shallow water fauna, and its relations to the other great 

 groups. The application of these general principles to 

 the special features of the area with which the Committee 

 is occupied will, I think, be wisely postponed until further 

 knowledge and experience of its fauna have been acquired. 



The materials for the preparation of this paper are mainly 

 derived from the reports of the various dredging and exploring 

 expeditions which have been sent out by our own and other 

 governments during the last twenty years. To the writings 



