1893] NEW-YORK MICROSCOPICAL SOCIEl'Y. 75 



6. Transverse section of white substance of spinal cord of 

 bear. 



7. Cornea of cat, stained with chloride of gold. 

 Exhibits Nos. 4-7 all by Carl Heitzmann. 



Meeting of February 17TH, 1893. 



The President, Mr. Charles S. Shultz, in the chair. 



Nineteen persons present. 



Mr. George H. Blake was elected a resident member of the 

 Society. 



The Corresponding Secretary read a communication from Mr. 

 K. M. Cunningham, of Mobile, Alabama, dated February 8th, 

 1893, and accompanying the donation of a slide of selected dia- 

 toms from the Florida diatomaceous clay, as follows : 



'"With the view of placing upon record in a more definite man- 

 ner the recent find of a fossil marine diatomaceous deposit de- 

 rived from the phosphate area in the vicinity of Tampa, Florida, 

 and of which I duly forwarded specimens to your Society, I have 

 made a further study of the same by microscopical preparations, 

 one of which is sent you herewith, and I would offer as a result 

 of that study the following observations as illustrative of the 

 character of the deposit. 



" From a portion of the cleaned material I selected free-hand 

 about seventy perfect and fractional discs, and, upon studying 

 the same in detail with a |- Zeiss objective, I can state that the 

 surface ornamentation on the various species of Coscinodiscus 

 found in the deposit prove to be hexagonal scales, which may be 

 partially or wholly detached from their discoidal bodies, thus 

 leaving smooth surfaces, with or without traces of the striate- 

 punctate places of union of the scales with the frustules. In 

 many cases where the reticulated ornamentation is wanting and 

 the surface of the disc is left smooth, innumerable minute diatoms 

 of various species may be seen, overlying the surface, or pos- 

 sibly forming a part of the internal or histological structure of the 

 shell, during the secretion or growth of the silicious layers of the 

 frustrule during its living state. Were this view to be enter- 

 tained, it would introduce an element of doubt in the present view 



