WITH DESCRIPTION OF A NEW BRACHIONUS. 59 



material, would be good enough to confirm or disprove this 

 suggestion. 



Brachionus pterodinoides sp. nov. (PI. 6, fig. 1). 



This new Brachionus, of which only very few specimens were 

 found, possesses a type of lorica new to the genus, and appears to 

 have done its best to try to deceive the systematic student by 

 making itself look as closely as possible like a Pterodina. For quite 

 a considerable time I was unable to decide whether the animal 

 belonged to the genus Brachionus or Pterodina until I found one 

 specimen with the foot and its two small toes protruding, which 

 decided the question. As will be seen on referring to PI. 6, fig. 1, 

 the lorica is nearly circular in shape, greatly compressed and 

 flattened dorso-ventrally, and possesses a foot-opening situated 

 just below the middle on the ventral plate, a most unusual 

 situation for a Brachionus, but usual in Pterodina. The dorsal 

 plate of the lorica is greatly extended posteriorly beyond the 

 foot-opening, and under this projecting cover the eggs are carried. 

 The lorica is smooth except anteriorly, where six small ridges 

 mark the continuation of the six frontal spines. The mental 

 edge is a nearly straight line and without indentation. As far 

 as could be made out in the few preserved specimens available, 

 the internal anatomy of this species appears to be normal. In 

 one specimen the wrinkled foot was extended, showing two small 

 pointed toes, as shown in fig. \c. The lateral antennae protrude 

 high up above the middle on each side. 



I am greatly indebted to Mr. F. P. Dixon-Nuttall for the 

 three figures giving an excellent idea of the form of this new 

 species and new type amongst the Brachionidae. 



Size of lorica, length 285 /x (l/89th inch), width 224 fi (1/1 14th 

 inch). 



Brachionus satanicus Rousselet (PI. 6, fig. 2). 



When describing this species two years ago * I had specimens 

 only which had been obtained in a plankton collection made in 



* Journ. Q.M.C., Ser. 2, Vol. XI., p. 162 (1911). 



