GENUS COCHLIOPODIUM— COCHLIOPODIUM BILIMBOSUM. 185 



Body when at rest spheroid or ovoid ; by transmitted light, viewed 

 from above, appearing as a usually translucent, granular, protoplasmic 

 mass, with coarser, darkly outlined granules, closely invested by a trans- 

 parent, colorless, doubly contoured, more or less distinctly punctate or 

 cancellated membrane, like the young colorless shell of Arcella. When 

 in movement, and viewed in the same direction, usually appearing more or 

 less completely surrounded by a delicate transparent zone of variable 

 width, and finely and regularly punctate. In the lateral view, usually 

 appearing more or less widely bell-sliaped in outline, with the fundus and 

 sides defined by a doubly contoured dotted line, and at the mouth with a 

 wide, more translucent, and more or less delicately punctate band defined 

 by a scarcel}' perceptible dentated edge. Interior protoplasm with a large 

 round nucleus toward the fundus, with variable proportions of highly 

 refractive corpuscles, crystals, vacuoles, and usually one or more contrac- 

 tile vesicles. Pseudopods mostly few, hyaline, of variable proportions, 

 conical, often irregular and sometimes furcate. 



Size. — In the spheroidal condition from 0.024 mm. to 0.056 mm. in 

 diameter. 



Locality. — In springs, ponds, ditches, and other quiet bodies of clear 

 fresh water, among algae and in ooze. Pennsylvania, New Jersey, Florida, 

 Fort Bridger, Wyoming Territory, and New Brunswick. 



The genus Cochliopodium was first clearly characterized, and its often 

 enigmatic appearances satisfactorily interpreted by those able investigators 

 of the Rhizopods, Drs. Hertwig and Lesser. The species under considera- 

 tion was named by them C. pellucidum ; but, as the same appears to have 

 been previously described by Auerbach under the name of Amoeba bilim- 

 bosa, according to the rules of scientific nomenclature I have felt it obliga- 

 tory to adopt the latter specific name. 



Cochliopodium bilintbosuni, represented in figs. 1-25, pi. XXXII, 

 is common among algae floating in the water of ditches and ponds, espe- 

 cially with Zygnema, Spirogyra, etc. From its minuteness it is easily 

 overlooked ; and in the younger condition, from the transparency and 

 undeveloped structural character of the shell, it is apt to be mistaken for 

 an Amoeba. 



At rest the animal may appear as a spheroidal or ovoidal, translucent, 



