Protozoa and Ilotifera at Havana, III. 361 



4. O. intermedius Davis. 



Infrequent, occurring during August on Ceratophyllum from 

 Thompson's Lake. 



5. O. mucicola Kell. 



A few examples of this species were found in Dogfish Lake 

 during September, 1895, on liiviilaria. 



Megalotrocha Ehrbg. 



Forming spherical colonies of many individuals ; corona 

 kidney-shaped or four-sided, with a deep ventral sinus; trunk 

 with two or four opaque warts on breast. 



6. M. albofiavicans Ehrbg. 



Colonies of this rotifer were found in Quiver Lake during 

 June and August, 1894, the clusters being attached to Cera- 

 topltyllum. In September of the same year young free- 

 swimming clusters were taken in the tow-net from the Illinois 

 Eiver. The young have a small corona and well-developed 

 eyes, and might easily be mistaken for Conochlliis were it not 

 for the presence of the opaque warts. In November a quantity 

 of vegetable matter was taken from the shores of Quiver Lake 

 and put into an aquarium, and in a few days several of the 

 colonies were found attached to the plants. During Septem- 

 ber of the following year it was found in Dogfish Lake. 



7. M. semibullata Hudson. 



This interesting form was not discovered until July of the 

 second year, when it was occasionally found in the weedy 

 waters of Flag Lake. It increased rapidly until the follow- 

 ing month, when it was very abundant. The colonies seemed 

 to hang by slender threads to stems of rushes and other 

 aquatic plants, and when disturbed would swim through the 

 water with a revolving moticm. I was one day watching 

 some of these colonies, when one of them, coming very near 

 the surface of the water, was pounced upon and quickly de- 

 voured by a water beetle, iJincutes. 



TROCHOSPHiERA SemPER. 



Solitary, free-swimming; body a perfect sphere; buccal 

 orifice on the spherical surface ; principal wreath dividing the 



