'Rotifer a of Natal. By Hon. T. Kirhnan. 2-11 



ovary is roughly horse-shoe-sliaped ; the left branch is narrow, con- 

 taining about 15 to 20 nucleated germ cells in single row, and always 

 bifurcates, giving off a shorter arm, whilst the right branch is shorter 

 and stouter, and it is here that the egg is formed and constricted off. 

 This peculiarly formed ovary is also unlike that of any other known 

 species of Pterodina. The two great retractor muscles are bundles of 

 strongly striated muscle-threads ; their position is ventral to the other 

 organs, but posteriorly the band divides, and some of the threads are 

 attached to the dorsal and some to the ventral plate of the lorica. 

 Lateral canals and vibratile tags could not be found in the mounted 

 specimen, but near the base of the stomach, on each side, I observed 

 a cluster of peculiar organs, looking like flagellate cells, the nature of 

 which I cannot determine, if they do not belong to the water-vascular 

 system. It will be necessary to examine the living animals in order 

 to decide this point. No similar cluster of cells have been noticed in 

 other Pterodina. The opening for the foot is circular, and near the 

 centre of the lorica on the ventral side, and the foot cylindrical and 

 of usual structure. 



Pterodina trilobata has not yet been found in Europe, and seems 

 to be a tropical form. 



The fourth species contained in the slides sent from Natal is 

 Scaridiam eudactylotum, a rare rotifer in England. 



I do not think it is quite correct to say that all rotifers having a 

 foot and toes always spin a thread as they move ; they can do so when 

 they like and when it serves their purpose, but they do not all do so 

 always. These threads, when present, are readily seen under a gool 

 dark-ground illumination. 



o* 



Since the above was read Mr. Kirknian has sent me another slide 

 containing some specimens of a small variety of Notops brachionus, 

 possessing two small hollow spines at the latero-posterior angles of 

 the body, which seems to be widely distributed in South Africa, for 

 last year I bred a single specimen of it out of dried pond mud 

 received from Ehodesia. 



The size of this animal, which I propose to call Notops brachionus 

 var. spinosus, is -£? in. (379 /a) in total length, and y^y in. (254 /x) 

 the body alone, and this is not more than about two-thirds of the sizs 

 of the European type of Notops brachionus. 



