468 



Balbiani on the Reproduction of Infusoria. 



r^—o 



Fig. 2. 



diately after reproduction. At other times they are so nu- 

 merous that their chain can only lodge in the interior of the 

 body on condition of folding several times on itself, as occurs 

 in certain Urostyla." In another place the writer informs us, 

 "When the eggs have reached their full development they 



exhibit the appearance of little spheres 

 whose bulk is noticeably uniform in the 

 same individual. But at this epoch their 

 transparency is so great, that they only 

 appear in the greater number of species 

 as simple spots surrounded by darker 

 granulations of the parenchyma. It is 

 therefore indispensable, in order to form 

 -a an idea of their shape and structure, to 

 treat them, with a reagent like acetic 

 acid, which augments their cohesion and 

 refractive power. The action of this 

 agent immediately exhibits little glo- 

 bules of a bluish or yellowish-grey, and 

 endowed with considerable powers of re- 

 fraction . The vitellus, of a homogeneous, 

 or finely granulated appearance, is seen, on being 

 crushed, to be composed of larger or smaller gra- 

 nules loosely adherent, and connected by a mass com- 

 posed of fine molecular granulations. The germinat- 

 ing vesicle is usually completely masked by the 



vitelline granulations, and cannot be 

 seen. Sometimes, however, it can be 

 shown by employing first a very dilute 

 solution of caustic potash, and then a little 

 iodine in water, or acetic acid. For the 

 same purpose ammonia and carmine may 

 be employed, which gives the vitellus a 

 rose tint, and causes the vesicle to ap- 

 pear as a more clear central spot." 



Although the eggs appear five in tlie 

 cavity of the body, M. Balbiani affirms 

 that they are enclosed in a membranous 

 canal, which is only the terminal portion 

 of the long, bent, tube resulting from 

 the metamorphosis of the ovary. His 

 view is exhibited in the annexed draw- 

 ing (fig. 2), taken from his published work, in which o, o, o, o, 

 represent the eggs, m, m, their tube open in m in the buccla 

 groove, <i, <i, are sterile fragments of granular matter, and 

 no trace remains of the spermatic capsules ; those not having 

 been employed in fecundation being absorbed. In fig. 3 the 



Tig. 3. 



77i — « 



Fig 4. 



