101 



LUC E UNA III yE AND THEIR ALLIES. 



assume this proportion, also, frequently near the partitions, in the region of greater 

 muscular activity {fi(j. 1U4, i). 



201. Vihmlile Cilia (^f 77).— In describing these bodies here the principal 

 interest to the histologist concerns their mode of relation to the cells upon which 

 they seem to be based. It is commonly received as a dogma that vibratile cilia 

 are direct prolongations of cells, forming an integral part of them. The most 

 recent investigations and teachings of our advnowledged leaders in histology have 

 reduced the typical idea of a cell to that of a mere concrete mass of " forming" 

 and " formed material" (see note, p. 97 et seq.), but have not divulged anything new 

 in reiiard to the vibratin": ciUvin. It is now some five years since we ventured to 

 announce our opinion that " aU vibratile cilia originate in the amorphous intercel- 

 lular substance.''' ' This has particular reference to those cilia that cover cells which 

 are fully developed, and have a distinct cell-membrane. It would be true, as a 

 matter of course, in the opinion of tliose who hold that Infusoria are composed of 

 sarcode, but apparently untenable if we admit with Kolliker, which we do not, 

 that they are unicellular. While we deny that these cilia are direct prolongations 

 of the cells which they seem to be so closely related to, we do not assert that they 

 are always disconnected with some form of cell in the modern acceptance of the 

 ideal cell. We do, however, believe that they are never the filiform proliferations 

 of a distinct cell-membrane, however much they may appear to be so, but that in 

 such cases they arise from the cytoblastema which overlies the cells. 



201 (A). We have now to offer new proof, supposing our observations to be cor- 

 rect, that the opinion announced in 1S63 is a true expression of the relation of 

 the vibratile cilia to the cells of the wall which they cover. Taking advantage of 

 the profile aspect offered by the oophragma (./'"y-s. 109, 110), as it curves over the 

 rounded contour of the genitalia, we were enabled to view the bodies in question 

 without any artificial preparation, such was the great range of adjustability of the 

 objective used in this investigation. We wish particularly to observe here tliat 

 the extent and thickness of the cytoblastemic intercellular substance in the 

 oophragma are rendered quite conspicuous by the abundance of granular matter 

 (e" e^) which is imbedded in it. By means of these granules we would, as it were, 

 locate, relatively, the position of the swollen, knob-like bases of the cilia. These 

 knobs vary in size and proportion to a considerable extent ; some of them are 

 scarcely wider than the ciliuni, while others are many times broader, with a propor- 

 tionate length (Jiff. 112, E to K). They are usually longer than broad, and often 

 elongate, oval, or fusiform (E K). In the latter case their points project to no 

 inconsiderable distance downward between the cells. As far as we can make out, 

 the larger proportion of the cilia arise at points alternate with the cells, but still, 

 here and there, some overlie them. When the cilia become separated, as they 

 readily do, from tlicir attachments, the knobs may be traced to their direct tran- 

 sition into the filamentary part without any doubt as to their relationship. We 

 have figured (fig. 112, E to K) several cilia in such a condition, not only from the 

 oophragma, but* also from the gastrophragma, at a point near the edge of the 



See I'roc. Boston Soc. Nat. Hist., Sept., 1863, p. 283 ; aud Anu. Mag. Nat. Hist., Dec, 1864. 



