1890.] NEW-YORK MICROSCOPICAL SOCIETY. 61 



3. The Diatom, Rhaphidodiscus Febigerii : by Geo, C. F. 

 Haas. 



4. Scales of 30 varieties of South American Lepidoptera : 

 by Thomas B. Briggs. 



5. Monazite sand from Brazil : by Thomas B. Briggs. 



6. Section of Hydro-magnesite, showing radiating crystalliza- 

 tion, from Hoboken, N. J. : by James Walker. 



7. Radiating crystals of Hydro-magnesite from Hoboken, N. 

 J. : by Geo. E. Ashby. 



8. Section of silicious Geode from the sub-carboniferous 

 shales of Warsaw, Illinois : by J. D. Hyatt. 



9. Section of silicious fossil Coral, Favosites : by J. D. 

 Hyatt. 



TO. Actinophrys sol : by Stephen Helm, of 417 Putnam avenue, 

 Brooklyn, N. Y. 



Mr. Hyatt described his exhibits with the employment of 

 black-board sketches, and stated that the geodes from Warsaw 

 are of all sizes, from one-half of an inch to a foot or more in 

 diameter, and, when broken, they are generally found to be hol- 

 low, with the cavity lined with crystals of calcite or quartz. As 

 the formation in which they occur, is entirely calcareous it is not 

 a little interesting to observe, as in this section, the complete 

 molecular change which some of them have undergone. The 

 side of the section representing the, exterior is chalcedonic, for 

 the depth of about one-eighth of an inch, showing the radiating 

 fibrous structure and peculiar polarization of that mineral. The 

 interior wall is compact crystalline quartz. 



The section of Favosites is also completely metamorphosed. 

 The cell-walls of the coral and the structure for a short distance 

 inward are chalcedony, while the interior of each cell is entirely 

 filled with microscopic quartz crystals. 



Mr. Helm described his exhibit, and also reported, that on a 

 late occasion he kept a female Daphnia in a minute drop of 

 water in a live-box over night, and that on the next morning — 

 after an interval of about eleven hours — he found her still living, 

 and having produced fourteen living young, " all the very image 

 of their mother." 



Meeting of January 30. 1890. 

 The President, Mr. Charles F. Cox, in the chair. 



