QUEKETT MICROSCOPICAL CLUB. 367 



of restraint is banisiied. With the 2/3rd in, and dark-gronnd 

 illumination many species may be identified, and it is a very 

 pleasant way of working through an afternoon's catch. Then, 

 again, there is plenty of scope for high-power work in solving the 

 difficulties of structure. Any rotifer may be identified with a 

 l/6th in., and such a power is necessary to see the small forms satis- 

 factorily. There is also scope for the highest powers, and a water- 

 immersion with correction collar is a very useful addition to the 

 outfit if the amateur has a really inquiring mind. The water- 

 immersion objective is valuable for examining both live and 

 mounted specimens (the latter being in weak formalin). Mr. 

 Maxwell had never been able to use an oil-immersion objective 

 adequately on any rotifer, alive or dead. As regards specimens, 

 the rotifer hunter is in a more fortunate position than most 

 microscopists, for there is no season of the year in which they 

 cannot be found, provided there is water. The types found vary 

 with the seasons, but there is no season at which none can be 

 found. Mr. Maxwell had even taken floscules and melicerta from 

 under several inches of ice. The best time for rotifers is in the 

 springtime, before the Crustacea begin to flourish, when they can 

 be found in suitable ponds, etc., in countless numbers ; but it is 

 not Mr. Maxwell's experience that the greatest variety of species 

 is found in such hosts of specimens. Eousselet was apparently 

 of the opinion that if search were sufficiently thorough it should be 

 possible to find in these islands all, or nearly all, the known species. 

 No slowly moving or still water should be neglected by the rotifer 

 hunter. Little temporary pools, drains at the sides of fields, 

 especially at the foot of grassy, mossy banks, old roof gutters are 

 all worth examination, and on one occasion Mr. Maxwell found a 

 cow-hoof mark, 5 in. deep, swarming with Synchaeta. The Club 

 haunts are good, said the speaker, but he thought the Mitcham 

 Common ponds, unless radically changed by last year's drought, 

 are worth serious investigation. He had found the rare floscule, 

 F. trifidlobata, there, and saw what appeared to be a rare species 

 of Apsilus, while there were also many different forms of Oecistes. 

 The best place for tube-building rotifers about London in his 

 experience is undoubtedly the Thames at Kingston, Ditton, and 

 Datchet. He had found a great many tube builders there and 

 in great plenty, also Cephalosiphon, Limnias, many forms of 

 Oecistes, and the beautiful colonial form Lacinularia socialis, 



