53 241 



Brachionus pala Ehrbg. 



Male: PUitc 1886, p. 65. 



Weber 1898, p. 672. 



PL XI, fig. 1-3. 



Plate (1886, p. 67, PI. III, fig. 25) describes the male under B. amphiceros. 



The wheel-organ is described as follows: "Der Räderorgan besteht aus einem coiitiiuiir- 

 lichen Wimpersaiinie, über den der Kopf halbkugelig vorspringt. Auf der ventralen Hälfte 

 dieser Calotte befinden sich noch eine Anzahl Cilien, deren Stellung und Grösse die Zeichnung 

 veranschaulicht. Die stärksten unter ihnen sind an der Spitze oft zerfasert." There is a iiidi- 

 ment of an alimentary canal: "Zwischen der Unterseite des Gehirns und der Rückenseite des 

 Hodens spannt sich als ein unregelmässiges Band der rudimentäre Darm aus. Das dies Ge- 

 bilde eine solche Deutung verdient, geht daraus hervor dass sein hinterster Abschnitt, der 

 also dem Enddarm entsprechen würde, blasenartig erweitert ist und dieselbe schwarze Körner- 

 masse enthällt, wie sie im Darm der jungen Weibchen vorkommt. Bei manchen Exemplaren 

 ist der Zusammenhang zwischen der vorderen und hinteren Hälfte des rudimentären Darmes 

 freilich nicht mehr vorhanden oder sehr undeutlich geworden." Brain with red eye; one dorsal 

 and two lateral antennæ. Two lateral canals, no contractile vesicle. Testis normal, penis longer 

 than foot; two foot glands. 



Weber (1898, p. 672, PL 23, fig. 16) gives a short description of the male. His figure 

 shows that he has seen the lateral canals, and four transversal muscle bands; his drawing 

 of the wheel-organ resembles mine; laterally round the forepart of the testis are drawn two 

 organs which I have not been able to find and the function of which I do not know. 



Description: Body cylindrical, provided with a short, inconspicuously divided 

 foot, with two small toes. A faintly developed lorica, consisting of a larger dorsal 

 and smaller ventral plate. No spines. The lorica very hyaline. The wheel-organ and 

 partlj' the foot can be withdrawn in it. A terminally placed wheel-organ, consisting 

 of a ciliary wreath, encircling a disc with three cushion-shaped elevations, carrjdng 

 a number of long, rather stiff cilia; further six strong setæ. Of the alimentary canal 

 only a rudiment, used as ligamentum for the testis. A large brain with a red eye 

 spot; two dorsal nerves, running to one single dorsal antenna and two lateral an- 

 tennæ far behind. Two conspicuous lateral canals with three pairs of vibratile tags; 

 no contractile vesicle. Testis large, pyriform, with two kinds of spermatozoa ; ductus 

 seminalis in its anterior part coated with cilia. Penis, when not used, withdrawn; 

 opening dorsally on the foot; when fully extended, thick, enormous, wrinkled, ta- 

 pering behind, ending in a body like a glans, provided anteriorly with a wreath of long 

 cilia. Ductus seminalis in its posterior part consisting of a chitinous lube, a real 

 penis, disc-shaped at apex and here bearing an opening. When fully extended, the 

 whole organ is much longer than the small fool, which hangs down venlrally as a 

 lateral appendix of the penis. When not used, the whole organ disappears in the 

 foot; it is pressed out, not so much by means of muscles as by means of blood 

 pressure. When it is fully extended the wheel-organ is withdrawn. Two prostata 

 glands. In the middle part of the penis two other glandlike bodies. Above the 

 testis a globular light-refracting body, containing numerous sharply edged opaque 

 grains, any connection with the rudiment of the alimentary canal I have never 



