Nev:) Species of Rotifer a and Protozoa. 313 



very fine points. Their inner edges are convex and 

 separated from each other, while the outer edges are 

 concave, consequently when viewed dorsally, the toes 

 are seen to be separated and to curve away from each 

 other. A ruby eye is situated in front of the large 

 mastax. The ovary is large and spherical. The stom- 

 ach, viewed dorsally, is pear-shaped, with large end to- 

 wards the anterior part. The eggs are carried about fast- 

 ened to the posterior part of the lorica. When the animal 

 withdraws into the lorica, the anterior edge is thrown 

 into a number of longitudinal plications. 



This species was found during July and August in 

 tows from the Illinois River and Phelps Lake. 



Length of lorica .228 mm.; width .150 mm. 



PROTOZOA. 



Of the eighty species of Protozoa observed, four ap- 

 pear to be new to science. Two of these, Diffiugia tio- 

 herculosa and Ceratium hrevicorne, were first found in 

 Matanzas Lake. 



Diffiugia tuberculosa n. sp. 



(Plate XXV.. Fig. 9 and 10.) 



Shell compressed, irregularly ovoid in shape, sightly 

 constricted around the mouth, and prolonged into 

 a short neck. Fundus rounded, and endiug in one 

 or more blunt processes, like D. pyriformis var. nodom 

 Leidy. On each of the compressed sides there ai*e three 

 small prominences or tubercles. 



This is a medium-sized species, about one and a fourth 

 times as long as wide. The shell is composed of large 

 and small rounded sand grains. No diatoms and 

 but very few grains of sand with sharp corners are 

 found in the shells. This species is characterized by 

 having three small tubercles on each of the two com- 

 pressed si dps. These tubproles are arranged on each 

 side of the shell so as to form the angles of a triangle. 



