72 THE WEST AMERICAN SCIENTIST. 



was formerly thought incapable of supporting either animal or 

 vegetable life. An official analysis of the water of the 'Dead Sea 

 of California', as it has been called, had just been received from 

 Washington and is as follows : 



Silica 0.28 



Ch oride of Potassium ... - 2.23 



Chloride of Sodium 18.22 



Sulptate of Sodium 10.07 



Borate of Sodium .20 



Carbo late of Sodium 19 49 



Carbona e of Calcium .08 



Carbonate of Magnesium. . .3.3 



Water 948.47 



Total 1,000.00 



Thus ^hoT^•^ng the remarkable proportion of nearly 52 parts of 

 solid constituents in each 1,000. 



Specimens were also show^n of the evaporated alkaline sediment 

 from Owens Lake, stained a bright red by the presence of enor- 

 mous numbers of the above-mentioned bacterium. Some further 

 communications regarding the flora and fauna of the Mono Lake 

 region have been promised the society by Dr. Harkness. 



HYDRA, THE FRESH-WATER POLYPE. 



Mr. A. H. Breckenfeld read a paper on Hydra, the Fresh- 

 water Polype, July 28, before the San Francisco Microscopical 

 Society. After referring to the original discovery of this remark- 

 able little creature by that pioneer microscopist, Antony van Leeu- 

 wenhoek in 1703, allusion was made to the investigations of Trem- 

 bley — by whom the animal was practically re-discovered nearly 

 forty years later^and the great interest excited thereby among 

 the naturalists of Europe. As to classification, Mr. Breckenfield 

 said that the genus Hydra, Linn., ranks only a little above the 

 protozoa. It is the lowest form of the great animal sub-kingdom 

 Caelenterata (sac-animals), which is divided into two great classes, 

 Hydrozoa and Actinozoa, and Hydra is the type of the former 

 class, just as Actinia (the sea-anemone) is that of the latter. Hy- 

 dra consists essentially of an elongated, nodular sac of protoplas- 

 mic substance, imbedded in which are found large numbers of 

 colored granules. At the upper end of this sac, is a simple open- 

 ing — the mouth— and just below this is a circle of tentacles, usually 

 from six to ten in number. At the lower extremity the body is 

 furnished with a flattened suctorial disk, by means of which the 

 animal attaches itself to filaments of algae, rootlets of duckweed 



