of Arenaceous Foraminifera. 203 



code nor holes can be seen ; but no one would be so hardy as 

 to make this assertion ; and who has ever watched a Lituola 

 in active life ? 



When, however, we observe the " labyrinthic " structure 

 of Dr. Carpenter (' Introduction to the Study of the Foramini- 

 fera,' p. 144) , homologous, in my view, with the shell-tubula- 

 tion of Nummulites, traversing the walls of Lituola canariensisj 

 D'Orb. (= Nonionina Jeffrey sii^ Williamson, ^Recent Fora- 

 minifera of Great Britain,' 1858, p. 34, pi. iii. figs. 72 and 73) 

 (PlateXIII. figs. 26-29), it is evident that, although large in the 

 greater part of their course, the tubular cavities of this structure 

 become contracted close to the surface^ and that this sudden con- 

 traction, short in itself and so short a distance from the surface, 

 thus brings the external ends of the "labyrinthic" canals 

 immediately into view on the slightest abrasion (fig. 27, V). 



Admitting, then, that the shell-tubulation of Nummulites is 

 but a counterpart of the " labyrinthic " canals, it is impossible 

 to conceive that the ends of the latter should be brought so 

 near the surface, if it were not intended that they should open 

 there for the same purpose as in Nummulites. Moreover, how 

 could the test of any kind of Foraminifera be added to exter- 

 nally if it were not for sarcodic filaments reaching the surface 

 here the same as in Nummulites ? Yet we learn from Dr. 

 Carpenter (' Introd.' p. 140), that the Lituolida " can only put 

 forth their pseudopodia from the terminal aperture," and that 

 therefore " the affinities of the purely arenaceous types are 

 essentially with the porcellaneous series" ('Introd.' p. 140). 

 But who ever saw the " labyrinthic " structure (necessarily 

 " labyrinthic" from the nature of tlie sandy material of which 

 the test is composed) in the form of a porcellaneous Forami- 

 nifer, or, indeed, the shell-tubulation which is the indication to 

 the pores on the surface? which pores, again, even here also 

 might be so small as to escape notice without this indication ; 

 lastly, whoever saw a porcellaneous test among the Num- 

 mulites, to which Lituola canariensis in form is most nearly 

 allied ? 



Here it should be remembered that the " pseudopodia " and 

 the filaments of sarcode which pass through the surface of the 

 test have totally different functions — the former for collecting 

 food, and the latter chiefly for forming the shell-substance. 

 Nowhere in Max Schultze's figures (' Ueber den Organismus 

 der Polythalamien,' 1854), which are by far the best that 

 were ever made, are the " pseudopodia " represented as coming 

 from the foramina on the surface of the shell, except in fig. 22, 

 tab. vii., where a few .filaments are seen to come from the 

 large apertures on the surface of a " young Kotalia." As a 



14* 



