105 293 



deutlichen Linsen versehen. Verd:uuingsappnrat fehlt; anslntt (le.sscll)en ist ein nniCangieieher 

 Hoden enlwicliell. Penis ist kurt und liegt auf tier Dorsalseile nahe hei tieni Körperende; dieses 

 ist verengt und liewimpert". Size of male 50 ft, of female 500 /<. 



Description. Male conical about four times broader in front than behind; 

 wheel-organ an apicallj' placed disc, encircled by a row of cilia. In the middle of 

 the disc a cone-shaped projection, covered with short cilia and provided with two 

 red eyes with well-developed lenses. The interior of the body a greyish mass 

 which only allows of a very superficial study. The brain is undoubtedly present 

 but its contours only faintly observable. Not the slightest remains of an alimentary 

 canal or excretorj^ organs have been observed. There is a large pyriform testis 

 and a ductus seminalis, covered with cilia in its interior; there are two well 

 developed foot glands. The genital opening apically; it is surrounded by cilia; the 

 last part of the ductus seminalis may be turned inside out and during the mating 

 process the body acuminates. I have not been able to see the slightest sign of trans- 

 versal muscles, but according to the movements of the animal, they are undoubtedly 

 present. Of longitudinal muscles only two slanting muscles have been observed. In 

 the greyish homogeneous mass are imbedded a lot of smaller and larger oil globules; 

 most conspicuous are a few very large ones, commonly situated dorsally before or 

 above the testis. Size of male 50 j.!,, of female 600 — 650 ,(t. 



On 27/IV 22 colonies of C. volvox were found in which resting eggs as well as 

 verj' minute eggs were found. The next day extremely minute creatures were found 

 encircling the coronas of the females. They were isolated and ascertained to be 

 males. They were incredibly variable in form. Encircling the coronas of the females, 

 they bent the body in all directions simultaneously; it looked as if the}' were dancing 

 a regular cakewalk round the selected individuals of the colonies; often more than 

 twenty males simultaneously encircled a single colony; then it very often happened 

 that two males butted against each other and then were flung out of their orbits, 

 away into the "empt}'" space, where they whirled round restlesslj' till they again 

 touched a colony in one of their large circles. I have tried in fig. 5 (Tab. XV) to give 

 a sketch of such a spasmodic male; it will be seen that the ductus seminalis has 

 been turned inside out and the cilia, now covers a distended ballshaped mass, upon 

 the tip of which the genital opening is seen. For a moment the males were often 

 fastened to the corona or directly below it; most probablj' this was the pairing act, 

 but it did not last more than a fraction of a second. 



Conochilus unicornis Rouss. 



Male: Rousselet 1892, p. 276. 

 Hlava 1908, p. 28. 



Rousselet (1892, p. 276, fig. 6) writes. 



"Tlie male is a small pear sliaped creature, with a small ciliated head and a large wreath 

 of cilia just below on a wider shoulder. Two red eyes in the head are conspicuous; the body 

 cavity is wholly taken up with the spermsack, and the pointed lower end is ciliated as 

 usual." 



D. K. D. Vidensk. Sclsk. Skr., naturv. og malheni. Afd., 8. R,-ekkc, IV, 3. go 



