544 
DE. CAEPEXTEE’S EESEAECHES OX THE EOEiXnXITEEA. 
ments ; and I am therefore strongly disposed to believe that Professor ]NLix. Schultze 
must have been misled by appearances when he stated (op. dt. p. Go) that various other 
parts of the septal plane are marked by similar pores, — more particularly as his figures 
of the decalcified body do not show that any other threads or stolons of sarcode pass 
from one of its segments to another, than those just described. 
187. So far, then, the structm’e of this comparatively gigantic t^-pe of Polystomella 
accords very closely with that of the more delicate species so well described by Professor 
Williamson. I have now, however, to give an account of a remarkable feature in its 
organization, namely, its highly developed canal-system ; which, though not enth-ely 
wanting in P. crispa, is so imperfectly presented there, that Professor Willlamson may 
well be excused for having overlooked it, especially when it is borne in mind that at that 
period the existence of such a system in Foraminifera was altogether unknown. The 
general arrangement of this canal-system may be most readily apprehended fi’om an ex- 
amination of the delineations of the internal casts given in Plate XATII. figs. 12, 13 ; for 
the infiltrating substance which has penetrated the chambers has also found its way not 
only into the main trunks, but also into the minute ramifications of this system, and has 
thus given just that representation of their distribution and relations, which is afforded in 
regard to the blood-vessels of the higher animals by a well-injected and clearly dissected 
anatomical preparation. We observe, in the first place, that in each of what may be 
termed the two polar regions of the spheroidal body, there is a continuous spiral canal 
(fig. 12, d, d\ fP), which overlies the extremities of the segments. These two spu'al canals 
(which, although so widely removed from each other, are obviously homologous with 
the two spiral canals of Operculina, ^ 169) communicate Muth each other by a very 
regularly disposed series of canals which pass in a meridional direction between the 
adjacent external margins of the segments (e, e\ e^). And each of these meridional 
canals gives off, in its course from one polar region to the other, a uniform succession 
of pairs of short passages (f,f\f^) that diverge from each other widely, one series 
inclining backwards over the uniform anterior margin of the segment next behind it. 
whilst the other series passes forwards in the intervals between the “ retral processes" 
of the segment next in front of it. The passages which thus diverge from the meridional 
canals of the outer whorl speedily debouch at its surface ; but if we examine into the 
termination of those appertaining to the inner whorls (which is best seen in such frag- 
ments as the one represented in fig. 13), we find that they become continuous with 
the stolons of the whorl which surrounds them, as is shown at c, c\ fig. 12. Further, 
it may be perceived that each of the meridional canals receives branches from the canal- 
system of the segment internal to it ; this point, however, can be more clearly made out 
in sections of the shell. 
188. The spiral canals are frequently brought into view for part of their course, b}' 
sections of the shell that pass through it in a direction parallel to the equatorial plane, 
but at no great distance from one of the lateral surfaces. Such a section, passing over 
the chambers of the inner Avhorls, is sIioaati in Plate X^TI. fig. 6 ; where we see the 
