143 331 



on putting a milky white glass plate immediately under the surface of a calm lake, 

 it will be seen that its surface film carries an enormous amount of resting eggs, 

 these are later on, when swept away by the autumn storms, deposited as dark lines 

 near by or upon its shores. 



It is this spreading of the impregnating material to innumerable individuals 

 which was in my opinion a conditio sine qua non for the remodelling of an 

 originally creeping organism into a freeswimming one, and which could only take 

 place at the sacrifice of the size and stage of development of the males. 



Thus I suppose we have some leading points that will enable us to under- 

 stand partly the underlying principles which made the reduction of the male sex 

 desirable for the species, and partly why the males if the species was to try to 

 fulfill the claims which were laid upon it in this respect must necessarily, owing 

 to want of food, be reduced in size. 



LIST OF LITERATURE 



Anderson, H. 



1889. — Notes on Indian Rotifers. Journ. Asiatic Soc. Bengal-Calcutta. 58, p. 345. 

 Apstein, C. 



1896. — Das Siiszwasserplancton. Kiel. 

 DE Beauchamp, p. M. 



1905. — Remarques sur Eosphora digilala Ehrbg. et description de son mâle. Arch. Zool. 



Exp., Paris, ser. 4, vol. 3, Notes et revue, pp. CCXXV. 

 1907a. — Morphologie et variations de l'appareil rotateur dans la série des Rotifères. 



Arch. Zool. Exp., Paris, ser. 4, vol. 6, pp. 1 — 29, text figs. 

 1907i. — Noiommata (Copeus) cerberus Gosse. Remarques anatomiques et systématiques. 



Zool. Anz., vol. 31, p. 905. 

 1908. — Sur l'interprétation de l'appareil rotateur dans les familles des Microcodonidés 



et Conochilidés. Bull. Soc. Zool. France, Paris, vol. 33, pp. 128 — 133, text flgs. 

 1909a. — Recherches sur les Rotifères: les formations tégumentaires et l'appareil digestif. 



Arch. Zool. Exp., Paris, ser. 4, vol. 10, pp. 1 — 410, pis. 1 — 9, text flgs. 

 1909Ö. — Philodina intermedia n. sp. et remarques sur l'origine des Microdinidés. Bull. 



Soc. Z»ol. France, Paris, vol. 34, pp. 75 — 84, text flgs. 

 1912a. — Sur deux formes inférieures d'Asplanchnidés (avec description d'une espèce 



nouvelle). Bull. Soc. Zool. France, Paris, vol. 36, pp. 223—233. text flgs. 

 1912Ö. — Instructions for collecting and fixing rotifers in bulk. Proc. U. S. Nat. Mus., 



Washington, vol. 42, pp. 181—185. 

 1912c. — Rotifères communiqués par M. H. K. Harring: Scaridium eudactylolum Gosse et 



le mastax des Dinocharis. Bull. Soc. Zool. France, Paris, vol. 37, pp. 182 — -187, text flgs. 

 1912rf. — ^Rotifères communiqués par MM. H. K. Harring et C. F. Rousselet: contribution 



à l'étude des Atrochidés. Bull. Soc. Zool. France, Paris, vol. 37, pp. 242 — 254, text flgs. 



