THE VIBRATILE ORAL MEMBRANES OF 

 GLAUCOMA SCINTILLANS, EHR. 



LEON AUGUSTUS HAUSMAN, Ph.D., 

 Cornell University 



Glaucoma scintillans was first described by Ehrenberg 

 in 1838, and has received since that time but little notice, 

 save as a species to be included in catalogues of micro- 

 fauna. The writer has found it of interest because of 

 the peculiar appendages borne about the mouth, i.e., the 

 vibratile oral membranes. Other species also bear either 

 one or two oral membranes, but Glaucoma is distinct in 

 this respect : that the membranes completely encircle the 

 oral aperture; are distinctly bilabial in form, and are 

 usually in active, characteristic motion. So rapid is the 

 motion of the membranes that, due to the reflection and 

 refraction of the light rays from the microscope mirror 

 which is produced, a twinkling or scintillating appear- 

 ance results. It is from this phenomenon that the crea- 

 ture has received its specific name, scintillans. 



The body of Glaucoma is ovate (Figs. 1 and 2), the 

 ventral surface flattened and entirely ciliated ; the dorsal 

 surface arched, and naked. The cuticle is everywhere 

 longitudinally striated. The oral aperture lies in the 

 anterior half of the ventral surface, its longer axis 

 slightly oblique, though in many individuals the longer 

 oral axis is practically parallel with the longer axis of 

 the body. The nucleus is spherical, its diameter being 

 approximately equal to the long axis of the mouth, and 

 situated in the central portion of the body, often, how- 

 ever, slightly nearer the posterior extremity. A sec- 

 ondary nucleus, roughly a fifth or sixth of the diameter 

 of the primary one, can frequently be made out. The 

 contractile vacuole is usually single, rarely double, and 

 situated in the posterior third of the body. In shape, 

 Glaucoma is more constant than many of the other cili- 

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