ON BEISTOL EOTITERS. 159 



well as of those which have been separated from each other on 

 the ground of red-spots, styles, caudal hairs, &c., &c., and of 

 similar minute differences. 



Of the above twenty-five genera no less than twenty-one have 

 representatives in the ponds round Bristol and Clifton, the 

 remaining four which I have not yet discovered, viz., Lacinularia^ 

 Tuhicolaria, Megalotrochay and Co7iocMlus, are probably to be met 

 with in some clean, clear, weed- clad, sluggish brook, if there is 

 such a thing in our neighbourhood. 



Floscularia cam/panulata is often to be met with in Garra way's 

 pond, near the White Ladies' road, and F. ornata I have 

 occasionally met with in Abbot's pond, at Leigh. 



Stephanoceros Eicliornii is very rare, but I have found it in 

 Garra way's. 



Melicerta ringens is to be found in many places —in the Portbury 

 ditches, in Abbot's pond, in ditches near Portishead, &c,, &c. 



Limnias ceratoplvijUi I have taken in the ponds close to the 

 railway station at Nailsea, and on algae growing on one of the 

 arches of a bridge over the Prome, near the Duchesses "Woods. 



CEcistes crystallinus is a frequent inhabitant of Garraway's pond 

 and of Abbot's pond. It sometimes occurs in myriads, covering 

 the algae and the stems and leaves of the lilies and water weeds. 

 It is a true Melicertan with a trochal disc, precisely of the pattern 

 of M. ringens^ though very minute. 



(E. longicornis is also to be found, though rarely, on the algae 

 in Abbot's pond. 



As to the various species of BracTiionus, nearly all, including 

 B. Mullen, are to be found in the farm-yard ponds about us ; the 

 latter is only occasionally to be met with in the Eedminster 

 ditches. It is a very large, handsome rotifer, and well worth the 

 studying. 



Pterodina patina and P. valvata are inhabitants of Abbot's 

 pond, and the former is to be met with in the Ploat ; the latter 

 very curious rotifer, which has the power of folding its lorica like 



