SPERMATIC PARTICLES. 37 



and Kdlliker* may be found nearly all that relates to the subject. My own observa- 

 tions have shown this much : 



Each of the large testicular cells arises from small nucleated cells, situated in the 

 stroma of the organ. I have seen them nucleated, and as small as one two-thousandth 

 of an inch in diameter. Soon after this, each has a nucleolus, and the whole incrcasin"- 

 we have regular nucleated cells inside of vesicles. Soon after this, the nucleus of the 

 cell (not the vesicle) begins to segment, until the cell is full of minute cells. The next 

 stage at which I perceived the progress was this mulberry mass composing the nucleus or 

 vitellus, disappearing and apparently replaced by a fasciculus of spermatozoa. (Vid. Fig. 

 1 - 5.) The stage of their real formation, or the metamorphosis of this granular cellular 

 mass into the bodies, I have always failed to observe. It has, notwithstanding, appeared 

 to me quite probable, that the filamentous bodies are formed by the gradual elongation 

 of the subdivided cells, and this because I have seen cell-like bodies of a more or less 

 pyriform shape, as though in a state of transition, and also because the subdivided cells 

 appear of too small a size to admit of a spermatic particle to be formed within them. 



However, according to both Hallman and Kolliker, they are formed within " vesicles 

 of formation." Although this may be the case in many instances, yet their production 

 in the other ivay does occur in other cases. At any rate, the discussion of these questions 

 does not appear to bear upon the grand formula of vitalization by segmentation. 



In the higher osseous fishes, where the testes are cither tubular or ampullar, the for- 

 mation appears somewhat dissimilar. Upon the inner surface of the tubes or ampullae 

 there are developed vesicles, simple at first, but which soon become nucleated. This 

 nucleus or vitellus soon divides, and this segmentation goes on until the parent vesicle 

 is filled with minute cells. Next, the vesicle has its cellular contents replaced by Sper- 

 matozoa, the cephalic portion of which is about the size of one of the subdivided cells, a 

 fact which would lead me to infer that they are these last, slightly metamorphosed. I 

 am, however, quite unwilling to entertain any opinion on this point, as my observations 

 have not been sufficient, and as it is, of all microscopy I ever Kandled, the most difficult 

 clearly and definitely to make out. (Vid. Fig. 6-11.) 



Spermatic particles of this form do not appear to be very dissimilar wherever they 

 occur ; and of many species of several families which I have examined, the differences 

 were fiir from being well marked. They consist generally of a pyriform body (the small 

 portion in front), to which is attached, when they are fresh, a remarkably thin tail. 



In my earlier observations, I denied the statement that they had a caudate portion, 

 which was certainly true of the specimens I examined, — as they were subjected to the 



* Op. citat. 

 VOL. V. NEW SERIES. 6 



