SPERMATOZOA. 127 



the same genus. Siphonophora jacece is thus said to 

 contain ten follicles in all. In masses so tangled, and 

 so liable to injury during dissection, it is not easy to 

 speak very decidedly on this point. Nevertheless, this 

 point of number would have some importance, if 

 Balbiani's views are correct, viz. that there is a close 

 numerical relationship between the sperm-fascicles of 

 the male and the ovarian chambers of the female. Here 

 it may be remarked that, just as germ-masses are 

 visible in the female foetus, so sperm-capsules may be 

 distinguished in the males just after their birth. 



4 6.— THE SPERMATOZOA. 



The sperm-cells of Insects, like those of other 

 animals, are furnished with a vibratile filament, which 

 some have likened to the filament of the vegetable 

 stamen. 



Notwithstanding the name, these minute bodies are 

 to be looked upon rather as a peculiar product of 

 organic growth within the sperm-capsules, somewhat 

 analogous to the fine moving processes of the ciliated 

 texture, than as distinct organisms.* 



If a gentle pressure on the abdominal rings of the 

 male Aphis be continued after the protrusion of the 

 penis, a copious escape of minute bodies from the 

 ejaculatory tube will be noted, and these will scatter 

 themselves throughout the weak solution of sugar or 

 albumen used during dissection. Difficulties occur in 

 the examination of these minute cells which constitute 

 the spermatozoa of Aphis. Pure water after a time 

 through endosmosis breaks them up ; but by a judi- 

 cious use of acetic acid or other menstruum, parts other- 

 wise invisible may be brought into view. These cells 

 contain a nucleus and also a nucleolus.* 



In all cases that I have examined, where the male is 

 adult, these cells have shown only a slight motion, 



* Dr. Allen Thomson, art. " Ovum," Todd's ' Cyclop, of Anat.' 



