8.S DIPS INTO MY AQUARIUM. 



it held on to the plant is forked at the end and slides in and out 

 like a telescope. Reproduction is effected by both summer eggs 

 and winter eggs. 



There are many kinds of Rotifers ; but I must not overload 

 my paper with technical names which would require for their 

 explanation more space than I can now command. I will, there- 

 fore, finish with a brief enumeration of the groups mentioned in 

 Professor Nicholson's Manual : — • 



The typical group is that of the Notommatina {Hydafinea of 

 Ehrenberg). These are all permanently free and never occur in 

 colonies. The integument is flexible and there is no tube. 



Stephanoceros (the garlanded Rotifer) and Flosadaria (the 

 Flask animalcule) are fixed, and the animal has the power of 

 secreting a gelatinous tube of a most beautiful and transparent 

 character. 



In Polyarthra there are fin-like appendages moved by muscles, 

 which Mr. Gosse regarded as homologous with the articulated 

 limbs of the Arthropoda. 



In Asplanchnia there is no intestine, the " stomach hanging 

 like a globe in the centre of the body-cavity." 



The genus Echinoderes has no limbs and the body is imper- 

 fectly segmented ; but there is a kind of proboscis, which can be 

 protruded. It is this genus more than any other that reveals the 

 affinity between Rotifers, regarded as a group of Scolecida or lower 

 worms, with the higher worms or Annelida. 



Huxley's Annuloida included Scolecida and Echi?ioderniafa, 

 while his Annulosa embraced the Vermes., and also Crustacea., 

 Insecta., etc ; but it must not be supposed that there is anything 

 worm-like about the appearance of Rotifers. Their affinity with 

 the Scolecida proper (water worms and parasitic worms) is based 

 on minute and embryological characters, into which we must not 

 enter now. 



{To be continued}} 



