one as the vacôÙuoôÙlated subôÙstance of an AcôÙtiôÙnoôÙsphaeôÙrium, we may see a very close reôÙsemôÙblance, or forôÙmal analogy, to an ordinary celôÙluôÙlar or ãparenôÙchyôÙmaôÙtousã tissue, in the close-packed arôÙrangeôÙment and conôÙsequent conôÙfigôÙuôÙraôÙtion of these vesôÙiôÙcles, and even at times in a slight memôÙbraôÙnous hardening of their walls. Leidy has figured76 some curious little bodies, like small masses of conôÙsolôÙiôÙdated froth, which seem to be nothing else than the dead and empty husks, or filmy skeletons, of AcôÙtiôÙnoôÙsphaeôÙrium. And Carnoyÿ£¢77 has demôÙonôÙstratôÙed in cerôÙtain cell-nuclei an all but precisely similar framework, of extreme delicacy and minuteness, as the result of partial solidification of interstitial matter in a close-packed system of alveoli (Fig. 220).
Let us now suppose that, in our Radiolarian, the outer surface of the animal is covered by a layer of froth-like vesicles, uniform or nearly so in size.