microscope. (500 — 700 diameters.) The figure XII, on the 

 third plate, represents the species Difflugia, found in 

 the sediment of the Croton water. Another animalcule 

 similar to an amcebial form, is the Actit^ophrys, re- 

 markable for the long, tentacle-like, so-called " Pseudo- 

 podia," with which its globular body is surrounded, and 

 which has not been fully represented on the wood-cut on 

 account of want of space. I 

 observed this interesting crea- 

 ture with another species Acan- 

 thocystis viridis, {Grenadier in 

 Z Z., 1869) during the July and 

 August of 1870, and September 

 of 1871. 



The class Infusoria, which 

 are higher organized, are large- 

 ly represented by the species 

 Colpoda, Monas, Paramecium, Cyclidium, Enchelys, 

 Nassula, Chilodon, etc. Of more interesting Infusorial 

 forms, I found Vorticella* Convallaria, Epistylis 

 Nutans, Volvox Globator, Spirostomum Ambiguum, 

 whose movements and organization can be very easily 

 observed with a magnifying power of 200 to 350 diame- 

 ters. The Vorticella consists of an inverted bell-shape 

 body, on whose open edges a number of vibrating fringes 

 (cilia) in constant motion, are placed forming a sort of 

 wreath around the top, which serve for locomotion and 

 the drawing in of food, while at the lower surface is 

 attached a leg-like projection consisting of a sheath with 

 a central, longitudinal, muscular band, whose one end 

 is fastened at the lower extremity, while the other 

 end is fastened to the bell- shape body. This sheath 



* W. Kueline verifi««*ed the muscular structure of the contractile band 

 of the Vorticella-stem, by experiments made with the aid of electricity. 



