232 AQUATIC MICROSCOPY FOR BEGINNERS. 



and with objectives immensely inferior to even the 

 cheapest and lowest grade lenses now at our dis- 

 posal. However, Rotifer vulgaris has three toes at the 

 extremity of a long foot, which is jointed and which, 

 by means of these telescopic joints, can be entirely re- 

 tracted into the body. 



Between the two ciliary lobes is a narrow cylindrical 

 projection ciliated at the truncate tip, and nearly al- 

 ■ ways bearing two little red eye-spots close together. 

 This is called the proboscis. 



When hungry, the Rotifer clings to the slide by her 

 three toes, expands the ciliary disks, and sends a food- 

 bearing current through the preoral passage to the 

 true mouth, the mastax. When desirous of changing 

 her locality, she may either loosen her hold by the 

 tips of her toes and be carried through the water by 

 the action of the frontal cilia, or she may fold the 

 ciliary lobes together, and go looping about by cling- 

 ing with the tip of the proboscis while she draws up 

 the foot, when, fastening it to a new place, she lets go 

 with the proboscis, extends the body, takes a new hold 

 with the foot, and thus moves forward rapidly, some- 

 what with the movements of the "measuring-worms." 



Rotifer vulgaris produces her young alive, and in that 

 connection is a problem which the reader has an op- 

 portunity to solve, or at least, to try to solve. It is 

 that although the living young has been seen to leave 

 the parent's body through the posterior intestinal re- 

 gion, the cloaca, it is not known how those young pass 

 from their free position in the mother's body-cavity, 

 to the cloaca whence they have been seen to issue into 

 the surroundirjg water. Another interesting fact is, 

 ^hat although Rotifer vulgaris is so common everywhere 



