292 



GRIFFIN. 



the culture. Whenever a proper interval had jjassed since the previous 

 infusion, a rapid increase of the Euplotes always took place, so that by 

 the third day after starting a fresh infusion the animals could be found 

 by hundreds in any drop taken from the under surface of the bacterial 

 sciim co'S'ering the water. The cultures usually reached their maximum 

 development two or three days later; a few hours after this stage almost 

 all the animals died. It was then impossible to bring about a multiplica- 

 tion of the animals in this jar by starting a fresh infusion until after 

 the processes of decomposition of the preceding one had been completed, 

 and the water cleared. Nevertheless, a few Euplotes could be found 

 near the surface of the water at any time during this period. 



A blue-green alga (an OsciUatoria) grew well on the sides of the jar 

 from the beginning, and probably helped to presen-e conditions favorable 

 to the Euplotes. The other protozoa died out gradually until at the end 

 of a year only one other form, a species of Lemljus, remained with the 

 Euijlotes. 



This Euplotes appears to be an undescribed species, very closely 

 related to E. vannus; comparisons therefore are closely limited to the two 

 forms. The new species is named in honor of the Hon. Dean C. Wor- 

 cester, who has been interested in the study of protozoa for many years, 

 and who has vigorously a.ssisted the rapid development of scientific 

 work and education in the Philippines. 



The form of the animal is shown in Plate I, figure 1, and Plate II, 

 figures r2. 3, and i. The ventral surface is always flat, the dorsal surface 



considerably elevated in nor- 

 mal individuals. The curva- 

 ture of the dorsal surface 

 varies to a considerable degree 

 in accordance with the amount 

 of food eaten, so that in a 

 fresh, rich infusion the ani- 

 mals are thicker bodied than 

 in an old or poor infusion. 

 In every culture some Euplo- 

 tes can always be found which 

 are much broader than the 

 normal, oval in outline, and 

 greatly flattened. 



After cultures liave passed 



Fig. 1. — Outline sketches of three of the deformed tjjgir nrime ffreatlv mal- 

 individuals which appear when cultures have -' o J 



passed their prime. Specimen A seems to be formed individuals are SOme- 



the result of an aborted division. ij^gj common. These are 



always much flattened, the dorsal and ventral surfaces are parallel, and 

 the thickness is sometimes only one-tenth of the width. A great distortion 



