F. ■«'. PHILLIPS ORSEIiVATIONS ON HOTIFERS. 115 



opinion with regard to these nervous ganglia, some denying their 

 existence altogether. Some time ago Sir John Lubbock contrived 

 to tame a wasp, and that wicked ' Punch,' commenting upon the 

 subject, recommended him to try his hand upon a Rotifer or a 

 Vibrio. This has always seemed to me to be a simply magnifi- 

 cent extravagance. Until lately I was extremely sceptical as to 

 the presence of nerves, yet, when watching a Hi/datina the other 

 day, I noticed that it made a succession of darts in different direc- 

 tions, and in each case it secured a particle of food, in a manner 

 that conveyed the idea that the action was the result of pre- 

 determination. 



Projecting from the back of the neck may be seen a tubular 

 organ, armed at the tip with minute bristles ; this was thought 

 by Ehrenberg and Siebold to be a siphon for the admission of 

 water for the purpose of respiration, but subsequent research has 

 made this theory untenable, and it is now admitted by all to 

 represent the antennoe of more highly organized creatures. There 

 is no heart or special circulating apparatus, but in place of this 

 exists what is called a " water-vascular system," which consists 

 of two long flexuous tubes, one on each side, to which are attached 

 several vesicles, which, by their undulatory and flickering motion, 

 keep up a constant circulation in these aquiferous tubes. 



Anotlier very important organ is the articulated tail-like foot 

 or pseudopodium. This is capable of great elongation and con- 

 traction, sometimes on the sliding principle of the telescope 

 (e.g. Fhilodina), and sometimes by contracting in wrinkles (e.g. 

 Brachionus). At the extremity there are usually two or three 

 spines, which in the different species vary very much in length. 

 When they are two in number, they look like a pair of scissors ; 

 when there are thiee, the middle spine is sliort. This organ is 

 used as a means of attachment, and it is able to take firm hold 

 of the most slippery substances, glass for instance. This tail is 

 also used as a rudder to steer with when the rotifer is in the 

 act of swimming. 



The body is protected externally by an integument which is 

 sometimes flexible and sometimes hard ; in the former case it is 

 shaped like a vase, pitcher, shield, or spindle ; whereas in the 

 latter it is of a hard horny consistence, and strongly resembles 

 the shell of a tortoise ; in this case it is termed the lorica, and 

 is shaped triangularly, or like a boat, and not unfrequently it 

 is armed with spines, or decorated with various markings. 



With regard to reproduction, comparatively little is known.. 

 It was asserted by Prof. Ehrenberg that the Rotifera were her- 

 maphrodite, and for a long time this was acce[)ted as a fact ; but 

 during the last few years much has been done to elucidate matters. 

 Distinct sexes have been discovered in several genera by Mr. Gosse, 

 Mr. Brightwell, and Dr. Hudson. The male differs so completely 

 from the female in organization, size, and appearance, that it is 

 frequently supposed to belong to a different species. On two or 

 three occasions I have met with rotifers which I had supposed to 



