188 FRESHWATER FAUNA 



with the usual ring-shaped air-float, but with little spines 

 terminating in recurved claw-like hooks (Fig. 60). 



Two or three species exist which are unprovided with 

 statoblasts : in one of these development appears to be 

 intraparental. 



The Eotifers, a vast number of which are of world- 

 wide distribution, multiply by two different kinds of 

 eggs ; one of them, protected by a hard, thick covering, 

 no doubt serves as a means of dispersal. An excellent 

 summary of our knowledge on this matter is given by 

 Dr. C. T. Hudson,* from whom I quote the following: 

 "How could these minute creatures, which are inhabi- 

 tants of lakes, ponds, and ditches, 

 contrive to spread themselves so 

 widely over the earth ? Take, for 

 instance, the case of Asplanclma 

 ebbesbornii, which, till quite lately, 

 had but one known habitat, viz., a 

 small duck-pond in a vicarage garden 

 Fia. 60. Gemmule or in Wiltshire. The very same animal 



Statoblast of a Poly- , , -. , , r . , 



zoan (Cristatelia has been found by Mr. Whitelegge 

 mucedo Cuvier). m t h e botanical gardens at Sydney, 



(x 40 about.) J J 



New South Wales. No doubt in 

 time it will be found elsewhere also: but how or when 

 did it pass from the one spot to the other ? 



" Again, there is the strange Floscule, F. MiUsii, . . . 

 which has been found almost simultaneously by Mr. 

 Whitelegge at Sydney, and Dr. Kellicott at Ontario. 

 The possibility of its journeying between two such points 

 seems quite as hopeless as that of Asplanclma ebbesbornii 

 passing from New South Wales to Wiltshire. 



"And such cases are numerous. How did Hydatina 

 senta and Brachionus pala get to New Zealand ? or Notops 

 brachionus and Rotifer vulgar-is to the top of Adam's 

 * Nature, 1889, vol. xxxix. p. 437. 



