PLATE X. 



PLEUROSIGMA ANGULATUM. 



Magnified 4900 diams. 



From a Photo-Micrograph by Dr. R. Zeiss taken with the 2 mm. Apocnromatic Objective 

 N. A. 1.30 and projection eyepiece 4. 



Collotype Ptg. Co., 2*2 High Hoi born, W.C. 



