( 



22 Our Fresh-water Entomostraca. — Chambers. 



front; front slightly sinus; surface marked by about seventeen 

 angular costa3 on each valve, which are simple except in the sinus 

 •where but one extends to the beak ; two others commence a little be- 

 low ; and on the mesial elevation of the other valve, where two bifur- 

 cate near the beak and again near the front. Interior unknown. ' 



Length a little less than j^^ths of an inch ; breadth, a little over 

 xVhs. 



This shell bears some resemblance, in the beak and cardinal area, to 

 0. (?J cUa. Hall, but very slight in other respects. I have seen only 

 one specimen, but it differs so much from any other species that there 

 seems no doubt of its being distinct. 



Pusitlun and localitij : Cincinnati Group, Warren county, Ohio. 



Oar Fresh-water Entomostraca ; by V. T. Chambers, Esq., of Coving- 

 ton, Kentucky. 



Life everywhere ! What myriads of living forms surround us in 

 earth, air, water, everywhere — except in the fire ; and if the ex- 

 periments of Dr. Bastian and other abiogenesists are reliable, then 

 their opponents are driven to the conclusion that there are multitudes 

 of living germs which can endure, without losing their vitality, de- 

 grees of heat greater than are sufficient to burn many other substances. 



But it is not of these minute and elementary forms of life, only dis- 

 cernible under the higher powers of the microscope, that I propose 

 now to write ; nor yet even of those higher forms of infusoria, as Par- 

 amecium, Stentor, etc., which swarm in every drop of stagnant water, 

 and with which all microscopists are familiar. 



Nevertheless, though much higher in the scale of organization, and 

 much larger than these forms, the little entomostraca require the aid 

 of the microscope for their elucidation, and even of its highest powers 

 for the study of their anatomy ; and though less numerous than infu- 

 soria, yet they swarm in incredible numbers throughout the summer 

 in the waters of our ponds and streams, and when the droughts of 

 summer have entirely evaporated the water, they and their eggs may 

 still be found in the moist earth, into which they likewise retreat from 

 the cold of winter. 



But what are the entomostraca? They belong to the anulose sub- 

 kingdom, together with insects, shellfish, worms, etc., and to the class 

 Crustacea, containing lobsters, crayfish, etc., forming one division of 

 that class. Dr. Baird, in his "Natural History of the 'British Ento- 

 mostraca," published by the Ray Society, says they " may be charac- 

 terized by their being all aquatic ; by their being covered with a shell 



