Protozoa and Uotifcra at Havana, III. 373 



from June to October. This was most frequently seen, 

 tliougli never very numerous, from December to June, with 

 occasional appearances in October and November and in 

 July. Found in the towings, mostly in Quiver Lake, and 

 not at all in Phelps, Flag, or Thompson's lakes. 



SCARIDIUM EhRBG. 



Lorica vase-shaped or pear-shaped ; very thin, transparent, 

 smooth, without spines or projecting plates ; head with a 

 chitinous cuticle, except in front ; eye single ; foot without 

 spurs ; toes very long. 



54. S. longicaudum Ehrbg. 



But few specimens of this rotifer were taken. It is re- 

 corded from the deeper lakes, from July to October. 



Family SALPINID^. 



Salpina Ehrbg. 



Lorica an oblong l)ox, furnished with spines, but widely 

 open at each end, split down the back ; head and foot pro- 

 trusile ; toes furcate, long, straight ; trophi submalleate ; eye 

 single, cervical. 



55. S. eustaia Gosse. 



In both years this species was present from June to Sep- 

 tember, with a single occurrence in October. It was found 

 in the Illinois River and the deeper lakes, but was not abun- 

 dant. 



Our specimens agree with the description given by Mr. 

 Gosse, but average smaller, the largest individual measuring 

 .23 mm. in length. 



Family EUCHLANID^, 



EuCHLANis Ehrbg. 



Dorsal plate with the median portion arched ; ventral plate 

 nearly flat, usually with a flange on each side ; eye single. 

 Members of this genus were frequently seen eating diatoms 



