222 FAMILY GLOBIGERINIDA. 



385. It is obvious from the foregoing description, tliat the nutrition of the spines must 

 be provided for either through the investment of their surface by external prolongations of 

 the sarcode-body, or through the penetration of its substance by prolongations of the sarcode- 

 body conveyed into it by the canal-system, or through both methods jointly. That the sarcode- 

 body is continued in the form of pseudopodial prolongations into the canal-system can scarcely 

 be doubted, when it is borne in mind that such prolongations are known to pass through the pores 

 which are scattered through the chamber- walls oi Rofalia, and to extend themselves through the 

 surrounding medium. After having made their way through the proper walls of the chambers 

 of Calcarina, they will probably coalesce again in the lacunar cavities on the exterior of these, 

 just as they coalesce to form a continuous layer of sarcode over the chamber-walls of Rotalice 

 or Polydomellce ; and from the aggregation of sarcode in those cavities a new set of pseudo- 

 podial prolongations will take their departure through the canal-system of the " supplemental 

 skeleton," just as a secondary set of pseudopodial filaments of sarcode are often seen to 

 diverge from the little agglomerations formed by the reunion of some of those that primarily 

 issue from the pores of the shell (1^33). The analogy of other Foraminifera, moreover, renders 

 it very probable that the prolongations of the sarcode-body which reach the surface through 

 the canal-system, will reunite upon it so as to form a continuous investment over the whole ; 

 and that this will be especially the case on the spines, appears to be indicated by the provi- 

 sion there is in the furrowing of the surface, for conveying the prolongations of the sarcode- 

 body to every portion of their exterior. 



386. One more fact remains to be noticed, which is of much interest as showing that 

 the growth of the spire and that of the " supplemental skeleton" are to a certain extent inde- 

 pendent of each other : — I refer to the departure from the regular form that frequently shows 

 itself in the later turns of the spire, which (so to speak) often " run wild" in a variety of 

 strange modes, examples of which are so well represented in Fig. XXXIII, a — f, that it is 



Fig. XXXVI. 



Abnormal specimens of Calcarina. 



unnecessary to refer to them in other than these general terms. The extension of spines 

 from the whole surface of the disk, in the mode represented in Fig. XXXIII, A, may in like 

 manner be regarded as a sort of " running wild" of the supplemental skeleton. 



