332 Mr. A. E. Verrill on neic American 



dingi, Thompson, occurs*. A. Midhausenn, Edw. (Fischer, 

 sp.) is found in Lake Loak, in the Crimea f- A few years 

 ago Prof. Silliman presented to the Museum of Yale College 

 a number of specimens of a new species, A. monica, V., which 

 he collected in Mono Lake, California, where it occurs in great 

 abundance associated with the larvffi of EijhydraX. The water 

 of this lake is very dense, and not only very saline but also so 

 alkaline that it is said to be used for removing grease from 

 clothing. I have been unable, however, to find any reliable 

 analysis of this water. It is said to contain biborate of 

 soda. Prof. Silliman informs me that the genus also occurs 

 in Little Salt Lake. It occurs in great abundance in Great 

 Salt Lake, Utah, as I am informed by Prof. D. C. Eaton, who 

 obtained specimens there during the present summer; but these 

 have not yet come to hand. The water of Great Salt Lake 

 has usually been described by travellers as destitute of all life ; 

 but according to Prof. Eaton it contains not only an abundance 

 oi Artemice^ but also various other small animals, insect -larvae, 

 &c. The density of the water is stated as 1'170, but doubtless 

 varies much according to the season §. It yields, according to 

 Dr. Gale, over 22 per cent, of solid matter 1|, while the Syracuse 

 Saline, one of the richest natural brines in the United States, 

 contains but 19"16 per cent.^ A few weeks ago, Mr. Oscar 

 Harger discovered another new species, ^._9'raci7is,V., near New 

 Haven, under very peculiar circumstances. On the long wooden 

 bridge across West River and the extensive salt-marsh on the 

 West-Haven side, are placed large wooden tubs filled with 

 water from various pools on the marsh, to be used in case of 

 fire. By long exposure to the sun and air, the water in these 

 becomes concentrated, and thus furnishes suitable stations for 

 the rapid increase of Artemice. On examining the tubs on the 



* Thompson, Zool. Reseai-clies, fasc. 7. pi. 1. figs. 11, 12. 



t Edwards, Crustac6s, t. iii. p. 370 (1840). 



\ Verrill, Proc. Boston Soc. Nat. Hist. 1866, vol. xi. p. 3 (the larvae 

 were wrongly referred to JEristalis) ; Packard, " On Insects inhabiting 

 Salt-water," Proc. Essex Inst. 1869, vol. vi. p. 41. 



§ The density of the water of the Atlantic Ocean is stated as 1-020, 

 that of the Dea Sea 1-130 to 1-227. 



II This solid matter, according to Dr. Gale (Silliman's Journal, ser. 2. 

 vol. xvii. p. 129), has the following composition : — 



Chloride of sodium 20-196 



Sulphate of soda 1 -834 



Chloride of magnesium 0-252 



Chloride of calcium trace 



22-282 



^ For analyses of several of these brines, see Dana's ' System of Mine- 

 ralogy,' p. 113. 



