4 
Transactions of the Society. 
II. — On the Male of Rhinops vitrea. 
By Charles F. Bousselet, F.B.M.S. 
(Bead 1 Zth December , 1896.) 
Plate I. 
Although Ehrenberg actually figured two male rotifers in 1838 lie 
did not recognise them as such, but described them as new species, 
and for ten years after the publication of his great work the Botifera 
were all considered hermaphrodite. The male of Hydatina senta 
Ehrenberg named Enteroplea hydatina , and he noted particularly 
that this was the only rotifer of which he could with certainty say 
that it had no trace of mastax and jaws. His second male rotifer he 
named Notommata granularis ; it is the male of a Brachionus, 
probably pala. Ehrenberg found some B. pala and also Notommata 
( Notops ) brachionus , carrying clusters of small eggs unlike the 
ordinary eggs, and out of these small eggs he saw his N. granularis 
emerge ; and he came to the extraordinary conclusion that N. granu- 
laris laid its eggs on the back of N. brachionus, Brachionus pala, 
and other species of Brachionus, which reminded him of the story of 
the cuckoo, and for a time these small eggs were called cuckoo’s eggs . 
All through his work Ehrenberg has described the contractile 
vesicle and lateral canals as the male organs of rotifers, and he was so 
convinced of the monoecious character of the class, that the idea of a 
separate male rotifer never for a moment entered his head. In 
1851 Dr. J. Weisse had repeated all these observations, and in 
addition had discovered the new species Biglena gramdaris, whose 
eggs, as he thought, he found lying amongst those of Biglena 
catellina, and he also noted that B. granularis had no jaws. After- 
wards he came to the conclusion that Enteroplea hydatina, Notommata 
granularis, and Biglena granularis were not different species, but 
that they were imperfectly developed, as yet toothless, young (“ unvol- 
lendete, noch zahnlose Junge ”) of respectively Hydatina senta, 
Brachionus pala and urceolaris, and Biglena catellina. 
But before this date, in 1818, Mr. Brightwell had made the 
important discovery and recognised the first male rotifer in As- 
planchna brightwelli, and in 1850 Mr. Gosse had found the male of 
A. priodonta. Then, in 1854, Dr. Leydig discovered the male of 
Asplanchna sieboldi, and declared his opinion that Enteroplea 
hydatina , Notommata gramdaris, and Biglena granularis were the 
males of the species with which Weisse had already associated them, 
although he himself had had no opportunity of seeing these males. In 
1855 Prof. Cohn confirmed Dr. Leydig and more fully figured and 
described the males of Hydatina senta and B. urceolaris, and 
in 1856 Mr. P. H. Gosse published his celebrated paper, ‘ On the 
Dioecious Character of the Botifera/ in w T hich he figured and 
