20 Mr. H. J. Carter on tJie 



appear to be similar in all. Grantia clathrus consists simply 

 of the spicular structure, the spongozoa (Geisselzellen), and 

 the granuliferous sarcocle (syncytium, Hiickel). 



The form of the spicules or skeletal support, which are 

 chiefly situated in the outer part of the wall of the hollow 

 thread, is of one kind only, viz. equiangular and equiradiate, 

 with simple straight rays, obtusely pointed, as already men- 

 tioned. 



The spongozoa do not appear to differ in form from those 

 of the other Calcispongiaj, but instead of being arranged in 

 juxtaposition around the interior of globular or sacciform 

 cavities, with their respective cilia projecting into the in- 

 terior, they appear to form in juxtaposition a continuous layer 

 throughout the inner surface of the tubular thread after this 

 manner. 



The " granules " of the sarcode, however, are very remark- 

 able from their size and dominant presence ; and although they 

 accompany the transparent sarcode everywhere, they a])pear 

 when in situ among the spicules and spongozoa to be loosely 

 grouped around a delicate nucleated cell respectively, the 

 " Kern " of Hackel. 



It is now thirty-five years ago that I gave an illustrated 

 description of this granuliferous sarcode in Spongilla (' An- 

 nals,' 1849, vol. iv. p. 91, pi. iv. fig. 2, a--f) in the living 

 state ; and as this seems to apply very nearly to that of Grantia 

 datJirus (so far as the dead state of tlie latter goes in a prepa- 

 ration to be presently mentioned), I will here quote the 

 original paragraph, viz. : — 



" If a seed-like body [statoblast] which has arrived at 

 maturity be placed in water, a white substance will, after a 

 few days, be observed to have issued from its interior through 

 the infundibular depression on its surface, and to have glued it 

 to the glass ; and if this be examined with a microscope, its 

 circumference will be found to consist of a semitransparent 

 substance, the extreme edge of which is irregularly notched or 

 extended into digital or tentacular prolongations precisely 

 similar to those of the protean \cimoehci\j which, in progression 

 or in polymorphism, throws out parts of its cell in this way 

 (pi. iv. fig. 2, dd). In the semitransparent substance maybe 

 observed hyaline vesicles of different sizes contracting and 

 dilating themselves as in the protean (fig. 2, ee), and a little 

 wnthin it, the green granules so grouped together (fig. 2,//) 

 as almost to enable the practised eye to distinguish in situ 

 the passing form [polymorphism] of the cells to which they 

 belong ; we may also see in the latter their hyaline vesicles 

 with their contained molecules in great commotion, and 



