132 Mr. H.J.Carter on the Oi^ganization of Infusoria, 



Rotifera open into the vesicula close to its communication with 

 the cloaca. 



It might be asked here, if all vacuolar dilatations of the sar- 

 code belong to this excretory system of sinuses ; that is, excepting 

 those made by the buccal cavity in the manner mentioned? 

 Certainly, where there is a plurality of actively contracting vesi- 

 cles, without the appearance of the vesicula, as in Chilodon cucul- 

 lulus, we may, as before stated, attribute this to a kind of over- 

 irritability or constrictive spasm of the vesicula, and, therefore, 

 consider that these vesicles are accidental dilatations of the sinuses 

 in connexion with it ; as we may set down the dropsical state of 

 Himantophorus Charon (Ehr.), and other animalcules of the kind, 

 to an opposite condition of this organ, viz. that in which it is 

 unable to relieve itself of its contents (fig. 84) : this I have ofteii 

 seen occur under my own eyes. But there is an intense vacuolar 

 state of the sarcode that occasionally presents itself in Amoeba^ 

 which makes it look like an areolar tissue composed of vesicles 

 diminishing to a smallness that cannot be determined by the 

 microscope, — such as is seen in the advancing border of Spongilla 

 when issuing from the seed-like body, and in the protoplasm of 

 the vegetable cell : whether this still be a part of the vesicula^ 

 system or not, I am unable to decide; at the same time, the con- 

 tracting vesicles in the transparent growing border of the new- 

 developing sponge are so numerous, and so like those which are 

 seen in the protoplasm of the last cell under formation of the 

 stem and roots of Chara when budding from the nucule, that we 

 cannot fail to see a most striking analogy between the two, even 

 if we cannot reconcile ourselves to the former being a part of the 

 vascular system attached to the vesicula; indeed, in the new 

 nucleus itself of the roots of Chara, vesicles do appear and dis- 

 appear. 



Lastly, from the presence of the vesicula in SpongUhf and its 

 being so constant in the Rhizopoda generally, and so numerous 

 in Arcella vulgaris, it does not seem altogether unreasonable to 

 infer that the streams of water which issue from the great canals 

 of Spongilla are produced by the continued pouring into them, 

 from the vesiculse of the different sponge-cells, the superfluous 

 water which they imbibe by endosmosis, apparently, during 

 nutrition ; for the type of Spongilla is to be surrounded with a 

 general pellicula, in which there is only one excretory opening, 

 and through which pellicula the ends alone of the spicula pro- 

 ject in bundles ; nor does it seem altogether far-fetched to con- 

 ceive that the offices of glandular organs in higher developments 

 may be performed, in some instances, after this fashion. "^ 



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