55 243 



Brachionus quadratus Rouss. 



Male: Marks & Wesché 1903, p. 508. 



Marks & Wesché (1903, p. 508, PI. 26, fig. 1) describe the male as follows. 



Stoutlj' fusiform in shape, a lateral view shows the heart and foot curvert rtownwards 

 when swimming free. Heart inclinert to be globular, a little variable in sliape, the constriction 

 of the neck also varies with position. Heart capable of retraction within the body. Horty cy- 

 linrtrical, stout, has marks of the ertge of the carapace, as in Diaschiza. A I'olrt of skin is sometimes 

 seen in rtorsal view. Foot stout, short anrt wrinkled, tapering from body and retractile. Toes 

 minute, triangular; sometimes a thread is spun from their extremities. Cilia long. Brain large, 

 three-lobed on the front. Sometimes oval glands seem to form part of it, in dorsal view. Ej'c, 

 rather nebulous, not well defined, faintly red, and variable in shape. Antcnnæ dorsal, well for- 

 ward on the head; lateral, low down on sides of body, as in the female, with long setie. There 

 is no digestive system. Lateral canals difficult to make out; at all events two flame-cells on 

 each canal. Two well marked foot glands. A very large sperm sack tapering from the centre 

 of the body cavity to the middle of the foot. A dark granular mass, contained in a vesicle 

 shows above the testis in dorsal view. Size: male 127 — 141 //. Time March 8th and 21st. 



Brachionus Bakeri O. F. M. 



Male: Rousselet 1897 c, p. 331. 

 RoussELET (1897, p. 331) says with regard to tlie males of the different varieties 

 of B. Bakeri, that they cannot he distinguished from each other. This is unques- 

 tionabl}' quite correct. I have often seen the males ; but they differ only slightly 

 from tliose of B. urceotaris var. B. riibens. 



B. angularis Gosse. 

 Tab. XII, lig. 1—2. 



Male: Description: Body elongate, provided with a very peculiar lorica, which 

 Gosse very correctly mentions as tortoise-shaped. There is a rather small, narrow 

 dorsal lorica and a much broader, but shorter ventral lorica, the posterior edge of 

 which is not seen with certainty. An inconspicuous divided foot with two toes. No 

 spines. Before the lorica a sharply defined part, carrying the ciliary wreath, surrouu- 

 ding a cone-shaped disc with about ten long, stiff cilia centrally and six long sehe. 

 Owing to the thickness of the lorica it is very difficult to see the interior organs. 

 No remains of an ahmentary canal are observed. There is a brain with a red eye 

 and a dorsal antenna and two lateral antennæ. Immediately below the shield, ex- 

 tending forwards from the dorsal antenna to the forepart of the lorica, is observed a 

 peculiar elongate structure, consisting of small grains, present in all the males 1 have 

 seen; it is possible that here we have a retrocerebral organ. Excretorj' organs have not 

 been observed. With regard to testis, penis, ductus seminalis, prostata glands and 

 sac with conglomerates, the structure of the male is in accordance with that of 

 the other Brachionis males described. Only a few longitudinal muscles arc ob- 

 served and no transversal muscles. No foot glands observed. Size of male 90/(, of 

 female 200 /<. 



B. angularis is, of all our Brachionus species, that which is niosl commonly 



