XOEXHtTMBEELAND AND DUUHAM. 85 



physiological relations, and the results of his researches were 

 published in the year 1835. Therein the true nature of Bkizo- 

 podous animals was demonstrated, their low organization satis- 

 factorily established, and the Foraminifera finally separated from 

 the Cephalopodous Mollusca with which they had hitherto been 

 associated. 



There is little that need be noticed in the more recent litera- 

 ture of the subject, although few divisions of the animal kingdom 

 have been written upon to the same extent or so variously. The 

 "more important works are well known, and easily accessible to 

 students. 



The conditions under which animals of purely microscopic 

 nature exist is obviously unfavourable to the preparation of a 

 local catalogue. In many classes of microzoa the difficulties are 

 insuperable, but there are circumstances in connection with the 

 distribution of the Foraminifera which permit the attempt to be 

 made with reasonable prospect of completeness. One of the most 

 important of these is the wide area over which the several forms 

 are found ; for, although the character of a Bhizopodal fauna is 

 influenced not only by latitude but also by depth of water, the 

 amount of variation from these caxises in a short coast-line, with 

 the depth of water seldom exceeding 40 fathoms, is scarcely 

 appreciable. The limited powers of locomotion with which the 

 little creatures are endowed, and the situation they most affect 

 (the surface of the mud or sand at the bottom of the sea) render 

 the collection of specimens by means of the dredge an easy and 

 productive process. Abundance of the shells of shallow water 

 species may be found in the shore-sands of our coast between 

 tide-marks, commonly associated with those of the smaller mol- 

 lusca and fragments of zoophytes. Whilst therefore some indul- 

 gence may be claimed on the . ground of the difficulties inherent 

 in the subject, it is not probable that many forms have eluded 

 the careful search made for them. 



The material which has been subjected to examination has 

 been derived in part from the dredging operations conducted 

 during the past three years under the auspices of the Field- Club, 

 and in part from littoral sands collected from the ripple-marks 



