222 Mr. H. . I. Carter on tlif ()r<inni~atinn of Infiistiria. 



opposite (fipt. 79). h\ Amwlm Gleic/ienii the nucleus itself oc- 

 ea.si(»ually presents a pellucid spot or punctuin in its centre. 



In I'urticvlln there is n lonu; cylindrical organ, which appears 

 analogous to, if not homologous with, the nucleus, and this, in 

 a large EpLt ijli.s comxnou here, and some other species of I'orli- 

 cclla, is wrapjud once rouiul the u])per part of the buccal cavity, in 

 the .same manner as the ovary is wrapped round the visceral organs 

 of Salpa among the Tiniieata (fig. 7'^g). Stein states that after 

 Vorticclla microstoma has become encysted, this organ divides 

 up into embryos, which, when the parent integument bursts, 

 come forth like " Manas co/jioda or Mont/s sciiiiii/ans" ; and he 

 " assumes " that these monads, after having become fixed and 

 stalked, pass into young VorticclUe* ; — an assumption which can 

 hardly be doubted, though it may be some time before chance 

 favours its demonstration. 



In Otostoiiia, and many forms of Ehrenbcrg's Enterodelous 

 class of animalcules, there is a similar organ, either of a cir- 

 cular, cylindrical, or fusiform, elongated shape (Annals, vol. xvii. 

 pi. 9. fig. 0). h\ Oxytrichu also there is something of the kind, 

 and in Himnnlop/wrus {Cliaron, Ehr., mihi) it extends nearly all 

 round the body, commencing from the posterior extremity, and 

 terminating on the right side close to the vesieula. 



The eyhndrical organ in Vorticelhi not unfrequently presents 

 a granular appearance, and the granules, which arc minute, but 

 uniform in size, appear to occupy the })cri])hery ; but whether 

 they are inside or outside the wall of the cylinder, or in the sub- 

 stance of the wall itself, 1 have not been able to determine. 

 Stein places them inside, in the form of a granular cylinder, and 

 within this " nucleoli t," — nucleated, discoid bodies, into which 

 the nucleus becomes divided. 



In the lihizopodous cell which inhabits the protoplasm of the 

 Characca'X, it is at first uniformly clear and transparent, then 

 semi-opakc and subgranular, afterwards two or more distinct 

 granules make their appearance, and finally it becomes wholly 

 granular and much enlarged ; or undergoes fissiparation and 

 thus gives origin to more cells, like the eytoblast of the vege- 

 table kingdom. 



Use. — It is impossible, in the present state of our knowledge, 

 to specify the uses of the nucleus. One j)oint, however, is evi- 

 dent, that it aj)pears very early in the development of the fresh- 

 water llhizopoda, sponge-cell, &c.; and another, that it bears a 

 close analogy to a similar organ in the vegetable cell, viz. the 



* Ann. and Map. Nat. Ilist. vol. i.\. p. 474 & 477- 



t Die Infnsionsthicre, &c. Taf. 4. fijj. 24. 4to, Leipzig, 1854. 



X Ann. and Mag. Nat. Hist. vol. xvii. p. 101, 185fi. 



