Rotifera of Natal. By Hon. T. Kirkman. 231 



-seen as they crawl over the glass or the debris that may be with 

 them. 



The thickness of the thread does not appear to be in proportion 

 to the size of the animal, but, apparently, depends more on the nse 

 to which it is put. According to my short experience, the term " free 

 swimmer," when applied to rotifers having either a foot or toes, is a 

 misnomer, as they invariably spin a thread and are moored to some- 

 thing either fixed or floating. 



I am in no sense an artist, and find it impossible to portray, even 

 with the camera lucida of Zeiss, the image of a rotifer satisfactorily 

 as it appears to me. Still I have made attempts at sketching a large 

 Pterodina that measures ^ in., and at giving an outline of a rotifer 

 that is a puzzle to me. This " puzzle " is a small illoricate rotifer, 

 tapering in an irregular manner to the toes. The corona is ap- 

 parently set on at an angle somewhat after the manner of Microcodon 

 clavus, as seen in the illustration given by Hudson and Gosse. It 

 has only one eye, which is situated at the bottom of the brain. The 

 trophi are sub-malleate, there being nine teeth in each uncus ; the 

 toes are small, pointed, and furcate ; and the foot I have never seen 

 in any way retracted. There is a brush of setae distinctly seen on 

 each side. The creature is as clear as crystal, the internal parts 

 being well defined, and it is always rotating at the end of its thread 

 after the manner of Synchseta tremula, but in an eccentric manner. 

 It takes from eight to fourteen turns in one direction, then reverses 

 and goes in the other. It is never fixed or quiet, at any rate under 

 the influence of light, for a single moment. It is impossible to 

 sketch it correctly, as it is never quiet, and pressure on the com- 

 pressorium destroys its appearance, and, for the same reasons, it is 

 exceedingly difficult to measure. 



Messrs. Hudson and Gosse, on page 36, vol. i., speak of the Ptero- 

 dinadce and Euchlanidae as " dwellers in clear ponds and rather 

 solitary in their habits." I have not found it so here. They certainly 

 like clear water, whether the quantity be small or great. I have 

 found what I take to be P. patina in numbers in various kinds of 

 small pools, from the size of one's hat to one which is in fact the hoof- 

 print of an ox in soft ground by the road side. I have collected 

 Euchlanis triquetra from a depression in a flat after heavy rain, and 

 also from a fissure measuring about 6 in. deep, 6 in. wide, and 18 in. 

 long, in a rock in the middle of a rapid stream after a day or two's 

 rain, and in considerable numbers along the edges among grass, &c, 

 of the placid pools of the river Umzinto, by merely plunging a bottle 

 into the water when the river is low after a period of rather severe 

 drought, as the last ten months have been in Natal. 



During our summer months, I intend to make some trials at pre- 

 serving and mounting rotifers according to the formula of Mr. 0. 

 F. Rousselet, F.E.M.S., and if I succeed, I will, later on, send what 

 appear to be new ones to the Royal Microscopical Society. 



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