354 GENEEAL HISTORY OF THE INFUSORIA. 



In a previous page we have stated the views of Carter and Perty, relative 

 to the existence of ova or germs in the inteiior of CiUated Protozoa, and 

 have rejected them as unsatisfactory. Further, when we come to inquire 

 the process of development of the presumed OM.iles, their mode of exclusion, 

 and other particulars necessary to complete their history and even theii' 

 identification, we find that those naturalists have no direct observations to 

 adduce, but can appeal only to analogy and to some casual and unconfiimed 

 observations of others. For instance, Mr. Carter, when treating of the develop- 

 ment of ovules, appeals to the process in Spongilla and Eiiglyplia, and endea- 

 vours to make out that,Tvdth some modifications, the ovules oiEuglence, and pro- 

 bably those of all the Rhizopods and Astasice, have a similar mode of generation. 



Perty, likewise, unable to advance any direct proof of the existence 

 of ovules and of their discharge, appeals to Eckhard's observations on Stentor 

 cceruleus, which Oscar Schmidt repeated and generally confirmed. In the 

 recorded observation of Eckhard {A. N. H. xviii. 1846), three or four 

 globules, in dififerent stages of development occurred in the interior of the 

 Stentor in a row (XXIX. 8-13) : — " In the fii^st stage, the contents of the 

 globules, consisting of minute granules, exist most imperfectly developed ; 

 but few granules at present occur, and the globule, when it lies in the 

 body, is not very distinct, on accoimt of the granular parenchyma of the lat- 

 ter. In the second stage of development (fig. 9) the granules appear more 

 numerous, the contents are therefore more concentrated, and the globules 

 can then be very distinctly observed in the body. Fig. 11 shows the third 

 stage ; granules commence arranging themselves in a row Or, as some- 

 times happens, they appear grouped in the same manner at two spots. The 

 gTanules thus arranged and closely pressed together, blend into a glandular 

 but clear organ (fig. 12), in which the granular structure cannot be any longer 

 detected ; frequently it is also divided in two parts. Lastly, in the situation 

 of the transparent glandular organ a row of cilia appears, evidently the mouth 

 (fig. 13). Whether this organ is formed immediately from the former, I 

 have not been able to ascertain with certainty ; yet that it is so, is extremely 

 probable, since on the one hand the row of cilia occurs in the situation of the 

 bright gland, whilst, on the other hand, in all the germs which exhibit this, 

 the former organ is absent. Simultaneously \\dth the development of the 

 mouth there appear one or two clear vesicles (fig. 13). On the 18tli of 

 May I observed in the interior of St. cceruleus a germ as in fig. 12 ; I saw 

 the cilia very distinctly in motion ; the vesicles were, however, still absent, 

 and they did not escape on this occasion. On the 21 st, I saw the perfect 

 form (fig. 13), which issued out, whilst the parent animal swam away. I 

 now attentively observed the young one to follow up its fiu'ther changes, 

 perhaps the bursting of the carapace ; but I was obhged to leave ofi* watching 

 it in half an hour, as I could not vouch for the accuracy of further observa- 

 tion on account of the strain upon my eyes. On the 4th of June I saw a 

 germ escape, as in fig. 13: it differed from that observed on the 21st of 

 May ; for, being at first roimd, it at once exhibited an incurvation at its lower 

 extremity — an appearance frequently observed in young Stentors, sometimes 

 in old ones, when they contract fi'om the elongated form to one more or 

 less rounded. I have subsequently once seen the escape of a similar germ ; 

 and it appears to me that the true point of maturity is that at which vesicles 

 begin to be visible. In Stentor polymorplms I have observed two such 

 globules, but I have not succeeded in seeing any perfectly formed escape. In 

 autumn I have often sought for the reciUTcnce of this phenomenon, but have 

 never been able to observe it so perfectly as in the spring, although similar 

 globules are not rare in the later parts of the year." 



