20 Ophrydiwm Versatile, 



and long ciliated oesophagus. The contractile vesicle is seated 

 r its end ; the nucleus is long, narrow, and twisted. The 

 exte rnal surface is thrown into close annular folds ; and usually 

 . mgitudinal plaits extend from the posterior end as far 

 Lddle of the body, which disappear when the body 

 contracts. A subjacent cortical lamina is evident, -and im- 

 bedded within this, numerous chlorophyll utricles, giving the 

 imal a vivid preen colour. When contracted, the body 

 .ones the form of a long-necked flask, and even the nucleus 

 shortens itself. In more complete contraction the figure be- 

 comes oval or globular. Fission is only longitudinal. When an 

 Oplvrydium quits its hold after fission, it swims away by means 

 of a temporarily developed posterior wreath of cilia, just like a 

 VorUcella. It is found encysted, and Stein believes in an 

 acinetiform phase. Vividly green and associated in smooth 

 and globular clusters or masses, which vary in size from a pea 

 to a ball five inches in diameter ; they are either free or attached. 

 Ehrenberg states that in May, 1837, he saw hundreds of clusters 

 as large as the fist, which, by the evolution of gas, were at 

 intervals elevated to the surface, and driven by the wind td the 

 edge of the water. In sea-water, also found by Brightwell, 

 in fresh-water, and in a small turf pit, upon tendrils of roots of 

 marsh plants, and the stalks of the white water-lily. Length 

 of single animalcule stretched out, 1-120" to 1-90"." 



From this description it appears that Ophrydium versatile is 

 an inhabitant both of fresh and salt water. I have never seen it 

 in salt water, but have met with it in canals and ponds. It may 

 be found throughout the whole of the year, and I have even ob- 

 tained large specimens from water which had been frozen over; 

 but in March and April the specimens appear to be most abun- 

 dant, and the most bi autiful both in form and colour. Fig. I 

 represents a single individual magnified about 400 diam.; the 

 ra<ed toin the description given above are clearly visible. 

 The animalcules are imbedded in a nearly colourless (not 

 " greenish" as Mr. Eteay Green states) gelatinous substance; 

 it is the animalcules themselves thai- give bhe green colour 



whole ball; they project their anterior extremities beyond 



the lly-like mass, and are firmly attached to its 



ab bancs by means of a very long non-contractile tail or 



peduncle, which breaks off from the body when the individuals 



Ice to a wandering mode of life. The gelatinous substance, 



which 18 homogeneous in nature, and not composed of nume- 

 rous little cells as Ehrenberg has stated, is often slightly 

 coloured with brown, which colour is caused by a parasite species 

 of Alga that Bends forth its Long twisting filaments into the 

 substance of the ball. The free animalcules, which are extremely 

 lively littl ires, swim about by means of their anterior cilia, 



