(I new Sj)ecies of Foraminifera. 315 



far the animal may make use of this latitude of movement in 

 bending the head this way or that by living contractile power, 

 as the occasion may require, I do not pretend to say ; but the 

 head is frequently bowed down on one side or the other, as if 

 the movement had been effected by the animal (fig. 2 a). 



The base of the pedestal, which is the bond of attachment 

 between the Sqiiamulina and the fucus or body on which it 

 may be located, and, although not so thick, is also chiefly 

 composed of the same material as the walls of the other parts 

 of the test, presents a radiated structure which, in a morpho- 

 logical point of view, becomes so interesting that 1 shall post- 

 pone it for more particular description and consideration here- 

 after (figs. 6 & 7). 



Meanwhile, the cavity of the test, like the test itself, con- 

 sists of two portions, viz. that of the pedestal and that of the 

 column. That of the pedestal more or less corresponds with 

 its external shape, presenting a circular hole at the summit 

 (fig. 5 a), which makes it continuous with the cavity of the 

 column, but is modified, in the rest of its extent, by a variable 

 number of pseudo-septal divisions of different lengtlis, five or 

 six of which, but generally five, are more prominent than the 

 rest, radiating inwards from the circumference of the pedestal 

 towards its centre, sliort of which they stop, to leave a central 

 area, but are continued upwards, so as partially to divide 

 the cavity of the pedestal into five or more circumferential 

 compartments, the septal prolongations between losing them- 

 selves upon the dome of the pedestal as they approach the 

 circular apertm-e at its summit, and thus causing the central 

 area to form a common cavity with the circumferential com- 

 partments, while it is in direct continuation with that of the 

 column. 



At the point where the cavity of the pedestal joins that of 

 the column, the union of the two is chiefly effected by chiti- 

 nous substance only, to admit of the motion of the column on 

 the pedestal to which I have alluded — a fact which, although 

 thus indicated, is only now and then satisfactorily seen, when 

 for some little distance at this point the outer or arenaceous 

 coat is absent (fig. 4rt). 



The cavity of the column itself {Hi) consists of a chain of 

 two or more chambers linked together by isthmic constrictions 

 corresponding to the dilatations and contractions respectively 

 of the column, which in full growth do not exceed three or four 

 of the former, as my illustration will show (fig. 3), terminating 

 at last at the summit of the column in the centre of the head 

 of spicules, by a constricted canal like those joining the dila- 

 tations, and ending ultimately on the surface in a small aper- 



