Observations on Notomniata Werneckii. By Prof. Balhiani. 543 



acquainted with N. parasita, which inhabits the spheres of Vohox 

 globator.* Another species, N. Petromyzon, Kves also in Vohox, 

 often in company with the preceding, t 



After Ehrenberg, N. parasita was the object of interesting 

 observations by John WiUiams,^ Gosse,§ and Ferdinand Cohn,|| 

 who discovered the male smaller than the female, and destitute of 

 digestive organs, like all the males of the Eotatoria. Cohn proved 

 also that N. parasita lays three kinds of eggs. 1st, numerous 

 summer eggs with smooth envelope, which give origin to females ; 

 2nd, eggs similar to the preceding, but smaller, whence issue males ; 

 3rd, winter eggs in fewer number, but larger, and with an envelope 

 bristling with short spines. 



I will close with the following resume of the principal results of 

 my researches. 



Notommata Wernecldi presents two periods in its existence, one 

 free, the other parasitic in the tubes of Vaucheria. In each of 

 these two phases of its existence it takes a very different form. In 

 the first it is elongated, vermiform, and divided into very distinct 

 segments externally ; in the second, in which it attains maturity, 

 it is dilated, sacciform, very contractile, and without segmentation. 



To these external changes correspond important modifications 

 in the internal organs, characterized chiefly by the enormous deve- 

 lopment of the ovary and the atrophy of the appendages of the diges- 

 tive tube (the salivary and gastric glands). 



Like many other Rotatoria, it lays two sorts of eggs — summer 

 and winter eggs, distinguished by their structure no less than by 

 their mode of development. 



The same female can produce either summer or winter eggs 

 exclusively, or a mixture of the two kinds in the same gall of 

 Vaucheria. 



The winter eggs are produced in the spring ; their laying com- 

 mences later and is prolonged longer than that of the summer eggs : 

 the latter develop immediately, while the former pass through the 

 winter, and only hatch in the following year. 



I have not observed any males, and on the other hand I have 

 never found any spermatozoids in the females, from which I con- 

 clude that the winter eggs, like the summer eggs, develop without 

 previous fecundation. 



The galls of Vaucheria, in which N. Werneckii lives and is 



* ' Die Infusionsthierchen,' 1838, p. 426, pi. 1. fig. 1. 



t Op. cit., p. 427, pi. 1. fig. 7. 



j " On the occurrence of Parasitic Eotifera in Volvox globator,'' ' Trans. Micr 

 Soc.,' 1852, vol iii. p. 129. 



§ " On the iV. parasita inhabiling the spheres of Vohox globator," ibid., p. 143. 



ti " Bemerkungen iiber Radeithiere," ' Zeitschr. wise. Zool ,' 1858, vol. ix. 

 p. 291. 



2 O 2 



