38 Mr. H. J. Carter on Microscopic Filaridse. 



ticiilar sac, from its small towards its obtuse end, too, corre- 

 spond with what they present when examined separately, after 

 forcible expulsion (14). Thus, the small end is observed to be 

 filled with small, delicate, nucleated cells (a) ; further on, these 

 are much enlarged ; then the mass presents a granular appear- 

 ance, which becomes more marked progressively as the granules 

 become larger (b) ; after which the granules assume an elongated 

 form, which is the first sign of their being spermatozoa; ra- 

 diated masses of spermatozoa now present themselves (c), and 

 lastly, the mass of spermatophorous cells after they have left the 

 parent cells, occupies the large end of the sac (d). 



How the radiated arrangement is produced, I am unable to 

 explain ; for, up to the time of the spermatophorous or daughter 

 cells leaving the parent cells, they appear to be disposed irregu- 

 larly round the inner surface of the latter — at least such is their 

 position after forcible expulsion (19 c?). It is not uncommon, 

 however, to see small parent cells containing a few spermato- 

 phorous cells with the spermatozoa radiating from one point 

 (20 a) ; nor is it uncommon to see groups of spermatophorous 

 cells without the parent cell, so attached together that all the 

 heads of the spermatozoa are directed to one point (20) ; but 

 on the other hand, as before stated, in the large parent cells, 

 which contain a great many spermatophorous ones, they appear 

 to be arranged irregularly round the periphery (18). If the 

 large masses in the testicular sac (14 c) could be expelled entire, 

 we might perhaps be able to see how this radiated arrangement 

 is produced ; but I must leave future investigation to point out 

 this, and to explain why, in the larger cells, after forcible expul- 

 sion, they have not this arrangement, or whether they ever have 

 it. Perhaps it is the forcible expulsion, after all, which destroys 

 the radiated arrangement. 



Again, as regards the spermatozoon : from possessing the 

 form mentioned, which appears to be the normal one (24), 

 many have the head of an intervening shape between bacilliforra 

 or linear and globular, but still always retaining the point or 

 beak ; while in the fallopian tube, sometimes, when the deve- 

 lopment of the ova appears to have ceased, and they have not 

 been required, they are observed to have passed into still longer, 

 bacillar, sharp-pointed bodies which have lost all vitality and 

 become rigid and brittle. 



Thus the development of the spermatozoa in their early stages 

 corresponds exactly with what I have described and figured re- 

 specting their development in Nais fusca^, that is, so far as the 

 production of the granules or daughter cells in a nucleated parent 

 cell is concerned, and these daughter cells becoming the sperma- 

 * Annals, series 3, vol. ii. p. 90, 1858. 



