Protozoa and Rotifcra at Havana, III. 377 



Metopidia Ehrbg. 

 Lorica usually depressed, entire, with an opening at each 

 end for the protrusion of the head and foot ; frontal hood in 

 the form of a hook ; foot and toes as in Coliirus ; eyes usu- 

 ally two. 



75. M. solidus Gosse. 



Of rare occurrence. Found in towings from Quiver Lake 

 in September. 



76. M, acuminata Ehrbg. 



No member of this genus was common at any time. The 

 present species was taken only in March, July, and Decem- 

 ber, in towings from the deeper lakes — Dogfish and Thomp- 

 son's. 



77. M. oxysternum Gosse. 



Eare. Found in towings from Quiver Lake and the Illi- 

 nois Eiver from September to December. 



78. M. rhomboides Gosse. 



This species was more numerous than any other member 

 of the genus. It was found in towings from the Illinois 

 River and deeper lakes during August and September, and 

 also once in December. 



79. M. triptera Ehrbg. 



This species was found in Quiver Lake during July and 

 August, and in Thompson's Lake in July. 



80. M. bractea Ehrbg. 



Found sparingly among vegetation and in towings from 

 Quiver Lake in July of both years. 



81. M. oblonga Ehrbg. 



Metopidia elUplica Turner ('92). 

 Found sparingly among vegetation in Quiver Lake and in 

 the river in June and July of the first year. Length of lorica 

 .105 mm. 



Family PTERODINIDiE. 

 Pterodina Ehrbg. 

 Lorica entire, greatly depressed, of two oval, but nearly 

 circular, plates united at their edges ; foot wholly retractile, 



