464 Balbiani on the Reproduction of Infusoria. 



genera. The nucleus, or female organ, exhibits three principal 

 varieties: (1) spherical, or ovoid; (2) tubular; (3) moniliforni, 

 or like a chaplet of beads. The nucleolus is much smaller than 

 the nucleus. <c The male and female corpuscules are often 

 united simply by their common envelop ; but in other cases, 

 not less numerous, the first is received in a depression (e'chan- 

 crure), more or less deep, of the second, where it sometimes 

 disappears entirely, but nevertheless preserves its own envelop, 

 although the confusion of the two bodies may be so complete, 

 that the hiding-place of the male corpuscule can only be dis- 

 covered by the employment of re-agents, such as diluted acetic 

 acid, which determines the condensation of their substance and 

 the visible separation of their walls/'' M. Balbiani divides 

 Infusoria into (1) " species whose ovary has the form of a little 

 utricle, or bag, of a rounded or ovoid form, containing an un- 

 divided mass of vitelline matter. In these the testicle during 

 its existence exhibits a similar appearance." Among these he 

 places Oolpods, Glaucomas, Paramecia, some of the Trachelia, 

 Nassula, Chilodons, etc. " In these species the ovary has con- 

 stantly the form of a little vesicle, usually situated in the middle 

 of the body, and completely filled with a granular matter, in 

 the interior of which the ovules are developed at the time of 

 sexual reproduction." (2.) " Species with an elongated ovary, 

 cylindrical, or tubular, variously curved or twisted, containing 

 a vitelline mass not presenting divisions (non fragments). 

 Testicle as in the former." To this division Euplotes, Aspi- 

 discus, most of the Vorticellids, Trachelius ovum, etc. belong. 

 In it "the male organ ^oes not participate in the elongated 

 or cylindrical shape of the nucleus," but in the instances in 

 which M. Balbiani has detected it, appears as " a little globular 

 or oblong corpuscule, free, or more or less entangled {engage) 

 with the substance of the ovary." (3.) " Species with an 

 elongated ovary, straight or bent, containing a vitelline mass 

 divided into two or more distinct fragments (ovary bi or multi- 

 locular). Testicle usually composed of an equal number of 

 elements which accompany the vitelline fragments, more rarely 

 of a single element." M. Balbiani remarks, " In the preceding 

 group we have seen the ovary affect the form of a tube more 

 or less elongated, in the interior of which a granular mass 

 extends without interruption from one extremity to the other 

 of the organ. If, instead of supposing this mass equally dis- 

 tributed through the ovarian tube, we conceive it divided into 

 a certain number of fragments which succeed each other with 

 regularity, and in the intervals we imagine the tube more or 

 less constricted, we shall have an exact picture of the arrange- 

 ment that we shall meet with in all the species composing this 

 group. The family of the Oxytrichians, reduced to its principal 



