6 Mr. W. C. Williamson on the Recent 



trading through the foramina in the calcareous cell, long exten- 

 sile tentacula or pseudopodia ; great bundles of filaments, which 

 projected from the surface, and especially from the umbilical re- 

 gion. These tentacula had also been noticed by M. Alcide D'Or- 

 bigny (see the Voyage dans L'Amerique Meridionale, tome v. 

 p. 29). 



In some further investigations into the structure of these cu- 

 rious creatures, in the memoir above alluded to (which is already 

 printed), I have come to the conclusion that a more or less dense 

 but elastic membrane lines the interior of each cell of the compound 

 Foraminifera allied to Rosalina globular is, Rotalina Bcccarii and 

 the Textillaria, upon which my observations were chiefly made, 

 prolongations of which membrane, injected from within (like the 

 processes which the Echinodermata push through the ambulacral 

 pores), constitute the pseudopodia observed by Ehrenberg and 

 Alcide D'Orbigny ; since, however large and distinct may be 

 the foramina in the external calcareous portion of each cell, no 

 trace of these foramina can be found in the membrane which 

 continuously lines the calcareous portions of the cells, when the 

 latter have been removed by acid. This internal membrane ap- 

 pears to have been filled with gelatinous matter, having appa- 

 rently very little organization — a condition noticed by M. l)u- 

 jardin, and which led him to regard the Foraminifera as little 

 more than an animated slime encased in an external calcareous 

 shell, and to associate them with the Pscudopodian Amceba 

 amongst the Infusoria. When the outer shell is removed by acid, 

 we often find that the different sacs of the inner membrane con- 

 tain numerous small siliceous organisms, which the animal ap- 

 pears to have swallowed, but which are scattered indiscriminately 

 over the whole of the cell in which they occur, and not confined 

 to any one line, which would have been the case had there been 

 any restricted portion, confined within special and narrow limits, 

 performing the functions of an intestinal canal. Hence it appears 

 probable, that, as in the case of the Hydra and some of the lower 

 infusorial animals, the whole cavity of the organism was one sac- 

 culated digestive organ, the various cells or divisions of which, in 

 those compound forms which are allied to Rosalina and Rotalina, 

 are connected together by one or more tubular necks ; channels 

 of communication passing through the septa, and along which the 

 food received could pass from one cell to another. How the rejecta- 

 menta made their escape is doubtful ; possibly, as is the case with 

 the Hydraform Polypifera and many other lower animals, the 

 oral orifice may be at once both mouth and anus. 



It will be understood, that, according to these views, the ani- 

 mal membrane which is left after the removal of the calcareous 

 portion is in reality an exact cast of the interior of the latter. 



