274 FRESH-WATER RHIZOPODS OP NORTH AMEEICA. 



to find the animal in an active condition and at the same time in a fixed 

 position. In one instance I found it attached to bladder-wort, Utricularia 

 vulgaris, and in another instance to the under side of a leaf of the water- 

 lily, Nymphcea odorata; both times in New Jersey. I have frequently 

 noticed dead specimens, and occasionally living ones, in an encysted con- 

 dition, among sphagnum collected in New Jersey and Pennsylvania. 



Clathrulina elegans is essentially single or solitary, though individuals 

 are often observed attached one or more to another in a candelabrum-like 

 manner, a half a dozen or even more together, thus assuming the appear- 

 ance of a compound animal, as exemplified by fig. 5. 



The mature Clathrulina consists of a spherical latticed capsule, com- 

 posed of silex, attached by a long thread-like stem of the same material to 

 some relatively fixed object, and containing a soft body resembling the 

 common Sun-animalcule, with its psendopodal rays projecting through the 

 apertures of the capsule. 



The silicious capsule is a superb latticed globe, reminding one of the 

 perforated ivory balls so well known as examples of Chinese skill and 

 patience. In young animals, the capsule is colorless and transparent, and 

 often continues in this condition at maturity; but usually, in the advance 

 of life, it assumes a straw-color, and in old specimens is frequently observed 

 of a dark yellow or even brown color. The apertures are large and com- 

 monly more or less polygonal, with rounded angles, but vary to circular 

 and oval, and are of nearly uniform size The bars separating the aper- 

 tures are narrow and rounded, and, according to Professor Greeff, are 

 grooved along the middle; but this feature escaped my attention. 



In different individuals the capsule commonly ranges in size from 

 0.033 mm. to 0.04 mm. in diameter. The apertures are from 0.004 mm. 

 to 0.006 mm. 



The stem of attachment of Clathrulina is of variable length ; some- 

 times comparatively short, and but little more than the diameter of the 

 capsule, but more frequently double, and to upward of four times the 

 length of the diameter of the capsule. It is highly flexible, and has the 

 same color and composition as the capsule it sustains. It is fixed to bodies 

 by an expansion or disk, usually somewhat lobate at the border. 



Though Clathrulina is commonly attached to plants or other foreign 

 objects, individuals often attach themselves to the capsules of others of 



