234 Mr. H. J. Carter on the Organization of Infusoria. 



complication, are observations merely put forth for what they 

 may prove worth. At the same time, it appears evident that 

 each organ must have its proper cell, and this cell its proper 

 mode of impregnative reproduction, just as much as the most 

 complicated beings of which it forms a part ; while the granu- 

 lating of the nucleus of a cell to furnish fertilizing germs for the 

 process of generation, when a simple division of it only is re- 

 quired for common reproduction, is perhaps not the least un- 

 tenable view that may be held on the subject. 



In Physnctis saccata, Kg., the spherical, terminal cell of the 

 snake-like filaments is filled or lined with a homogeneous, trans- 

 lucent substance, in one part of the circumference of which is a 

 nucleus, and this part is invariably next the last granuliferous 

 cell of the filament (fig. 70 6), which with the four or five fol- 

 lowing ones unite together to form the elongated club-shaped 

 sporangium (fig. 71). When the sporangium is completed, the 

 spherical cell is seen to be united to it by a kind of neck, but 

 the nucleus and its homogeneous contents have disappeared, 

 that is, have passed into the sporangium (fig. 71 «). While 

 here and there may be seen spherical cells unattached to (pro- 

 bably separated from) their filaments, some of which have a gra- 

 nular substance growing out in a linear form from the nucleus 

 (figs. 72, 73) . Hence then, as we have the nucleus of the sphe- 

 rical cell applied to the terminal cell of the granuliferous chain, 

 a tubular prolongation connecting it with the sporangium, the 

 disappearance of the nucleus and other contents of the spherical 

 cell after the formation of the sporangium, together with a gra- 

 nular growth from the nucleus of this cell when the sporangium 

 is in process of formation, I think it may fairly be inferred, that 

 the chief part which the spherical cell adds to the sporangium is 

 this granular growth from its nucleus. 



Development of the Ovule. — In Spongilla and Euglyphaj this 

 appears to take place by the passing of the transparent, faint- 

 yellow film, which lines the interior of the capsule, into an opake, 

 yellowish, granuliferous membrane ; synchronously with which 

 it becomes more marginated towards tlie capsule, and presents, 

 in the centre, a pellucid area, in the middle of which, again, is 

 a minute granule or body, which appears to be the rudiment of 

 the nucleus (fig. 59). Frequently, also, another layer, as before 

 stated, is seen in the ovules of Spongilla external to the capsular 

 one, and this appears to be endowed with locomotive power, as 

 it generally presents a parabolical shape, extended out from one 

 side of the ovule (fig. 40 a) ; after which the ovule in each be- 

 comes transformed, apparently wholly, into a polymorphic, rep- 

 tant Rhizopod (tig. 39 i, k). The same process, modified, appears 

 to take place in the ovules of Euglcna. Thus in E. viridis, where 



