â54 



66 



DE Beauchamp 1909, p. 24 — 25). The maies of Harringia are unknown, that of As- 

 planchnopus has been seen by Plate and rather superficially studied by Weber. 

 The males of the genus Asplanchna belong to the oldest and best known of the 

 Rotifera males. 



Asplanchnopus myrmeleo Ehrbg. 



Male: Western 1888, p. 647. 



Hudson Gosse, Suppl. p. 15. PI. XXXII, fig. 13b. 

 Weber 1898, p. 384. 

 Plate 1886, p. 83. 



Western (1888, p. 647) has briefly described the male as follows: 



The presumed male is found in a trough filled with water, where the female A. myrmeleo 

 was then abundant. "It had the cliaracteristic foot of the female. The brain is large, tripartite; 

 an eye spot; two dorsal antennæ; a very large contractile vesicle, and numerous vibratile tags. 

 There are the usual sperm-sack and protrusile penis, the latter lying behind the foot under a 

 valve-like flap. — Size female: ,}r„ of male ia'." 



Weber (1898, p. 384. PI. 16, fig. 11) has observed the male only in one spec- 

 imen. He only says: 



"II possède un repli membraneux, en forme de valvule, qui fait saillie en arrière du 

 pied et protège le pénis. Le testicule et le pénis sont placés plutôt transversalement dans la 

 cavité du corps et très en arrière." Size of female 960 fi à 1000; of 

 male 460 à 500 ß. 



Plate (1886, p. 83) remarks: 



"Von den bis jetzt noch nicht bekannten Männchen ist mir nur 

 einmal ein halbtotes Tier zu Gesicht gekommen, das hinsichtlich der 

 äusseren Gestalt so gut wie nichts erkennen liess. Der Hoden war dicht 

 gefüllt mit runden Zellen, halbreifen Spermatozoen und jenen schmal- 

 spindelförmigen unbeweglichen Körpern, die auch bei allen andern 

 Männchen beobachtet sind. Ein Teil derselben flottierte frei umher, 

 andere aber sassen mit ihrer Mitte den runden Zellen an, von denen 

 sie daher offenbar gebildet werden." 



It will be seen that the male may almost be regarded as 

 unknown. For many years I have in vain searched for this 

 form which, because of its intermediate stage between Harringia 

 and Asplanchna, is of the greatest interest. Finally in the autumn of 1921 I found 

 the animal in numerous little ponds, spread over a remarkable stone-covered heath 

 in the middle of Seeland near Sorø (Rejstrup Oredrev). Only females with large 

 yellow resting eggs were observed. 



Asplanchnopus myrme 

 leo (J . after Weber. 



Asplanchna. 



A rather long series of Asplanchna-species have been described. The main forms 

 are the following. 



