415 



On the Male of Proales wernecki. 



By Charles F. Rousselet, F.R.M.S. 



{Read June 18th, 1897.) 



Plate XIX. 



Up to last year the male Rotifers were all considered sadly- 

 neglected by nature, being diminutive in size compared with the 

 females, and wanting in many essential organs necessary for a 

 comfortable existence of some duration, such as a mouth, jaws, 

 oesophagus, a stomach and intestine. The only recorded exception 

 seemed to prove the rule, as it occurred in the very aberrant and 

 parasitic rotifers of the genus Seison living as ectoparasites on 

 Nebalise. 



In the spring of last year, however, I discovered the male of 

 Rhinops vitrea, which, while small in size, possesses fully developed 

 jaws and functional digestive organs. A description of this male, 

 with figures, will be found in the Journal of the Royal Microscopical 

 Society, 1897, pp. 4-9, and PI. I. 



In the early part of the same year Professor W. Rothert, of 

 Kazan in Russia, discovered another male rotifer : that of Proales 

 (Notommata) wernecki, possessing fully developed jaws and mastax, 

 and a somewhat rudimentary stomach and intestine. A very full 

 account of this discovery and description of both male and female 

 was published by Professor Rothert in the Zool. Jahrbiicher, 

 Bd. IX., Heft 5, 1896, pp. 673—713, but without any figures of 

 the male. This male of Proales ivernecki was also discovered 

 early this spring both by Mr. F. R. Dixon-Nuttall and by myself, 

 quite independently, and before we knew of Professor Rothert's 

 paper. 



At the conversational meeting of the Qnekett Club of April 2nd 

 Mr. W. R. Traviss exhibited some Vaucheria with numerous galls 

 inhabited by this well-known rotifer, which he had found in a 

 ditch close to his house at Willesden. A few days later Mr. Traviss 

 sent me some of this Vaucheria, part of which I at once forwarded 

 to Mr. Dixon-Nuttall. On examining the galls containing the 

 enormously distended females of P. iver?iecJci, surrounded by large 



