3 2 THE PENEROPLIS. PAET in. 



between the chambers, which increases with the age of 

 the animal and size of the shell. There is but one pore 

 in each of the consecutive partitions from the globular 

 centre to the fourth chamber. From the fourth to the 

 seventh chamber the communication is by two pores ; 

 after this the number is gradually increased to three, 

 four, six, &c., up to forty-eight, so that the last seg- 

 ment may send out forty-eight pseudopodia from the 

 mouth of the shell. In its early youth one pseudo- 

 podium appears to have been sufficient to find food for 

 the animal, but as the shell increased in size and the 

 segments in number, a greater supply of food was 

 requisite and a greater number of pseudopodia were 

 necessary to fish for it. Moreover when an addition to 

 the shell is required the pseudopodia coalesce at their 

 base and form a continuous segment upon which the 

 new portion of the shell is moulded. 



In varieties of the Peneroplis where the spire is less 

 compressed there are sometimes two rows of pores in 

 the partitions between the chambers. The Dendri- 

 tine variety deviates most from that described. It is 

 characterised by a single large aperture in each par- 

 tition which sends out ramifications from its edges. 

 The form of these openings depends upon that of 

 the spire ; when compressed the aperture is linear 

 and less branched at its edges; but in shells which 

 have a very turgid spire it is sometimes broader than 

 it is long, and much branched ; but these extremes are 

 connected by a variety of forms. The shells of this 

 variety of the Peneroplis are strongly marked by 

 the depressed bands and striae, as in the Dendritina 

 elegans (P, fig. 97). The segments of the animal 

 inhabiting these shells must be more intimately con- 

 nected than in most of the other Foraminifera ; and 

 the pseudopodia sent through these large apertures 

 out of the mouth of the shell must be comparatively 



