132 Mr. 11. J. Carter on the Orr/niiization of Infusoria. 



RotifiM'ii open into tlie vrsicula close to its conimunication with 

 the cloai'a. 



It iiiiirht l)e asked here, if all vacuolar dilatations of the sar- 

 code belouir 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, w ithout the appearance of the vcsicula, as in Ghilodon 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 w ith it ; as we may set down tlie dropsical state of 

 Himarito}iliurii.<! Clmron (Khr.), and other animalcules of the kind, 

 to an o])posite condition of this organ, viz. that in which it is 

 unable to relieve itself of its contents (fig. 81) : this I have often 

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

 state of the sarcode that occasionally presents itself in Amopha, 

 which makes it look like an areolar tissue com])oscd of vesicles 

 diminishing to a smallness thqt cannot be determined by the 

 microscope, — such as is seen in the advancing border oH Sponfji/la 

 when issuing from the seed-like body, and in the proto))lasm of 

 the vegetable cell : whether this still be a part of the vesicular 

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

 tracting vesicles in the transparent growing border of the new- 

 dcveluj)ing sjxinge are so numerous, and so like those which are 

 seen in the protoplasm of the last cell under f(jrmation of the 

 stem and roots of ( 'ha r a \\\ivn 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 C/iara, vesicles do appear and dis- 

 appear. 



Lastly, from the j)resence of the vesicula in Spoiujilla, and its 

 being so constant in the Rhizoj)oda 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 Sjj07U/ii!a are produced by the continued pouring into them, 

 from the vesiculai of the different sponge-cells, the suj)crfluous 

 water which they imbibe by endosmosis, a|)|jarently, during 

 nutrition ; for the type of Sponfji/la is to be surrounded with a 

 general ])ellicula, in which there is only one excretory opening, 

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

 ject in bundles ; nor docs 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. 



[To he continued.] 



