Entomostraca from Jerusalem. 37'i 



the pool being for the most part filled with .surface-water 

 during the rainy season. 



On descending into it I observed that at the end where the 

 water had rested last the thick layer of alluvial mud, which 

 covered the floor of the pool to a depth of a foot or more, was 

 densely silvered over with minute shells. These on examina- 

 tion proved to be the shields or carapaces of several kinds of 

 Eintomostraca. 



It occurred to me that, as the pool only contained water 

 during two months in the year, these animals, after so brief a 

 life, must leave their ova in the mud, to reprodu3e their 

 several sj)ecics in the next rainy season, after entombment in 

 the Sim baked mud for ten months. 



The idea of testijig the truth of this artihcially occurred to 

 me, and 1 took up carefully several pieces of tlie mud which 

 had cracked in drying; these, as I knew nothing of theEntomo- 

 sti-aca myself and was without books of reference, I sent to my 

 friend Mr. Denny, A..L.S,, then Curator of the Leeds iluseum, 

 Avith instructions when to moisten the mud. The result in 

 his hands was such as to surprise and delight him. One 

 alter another new species of several genera sprang into life. 

 Wisely he iiad not moistened all his mud ; so he sent a little 

 to Dr. Baird, of the British Museum, who was equally 

 charmed with the experiment. Dr. Baird described and 

 figured five new species in the Ann. & Mag. Nat. Hist., Oct. 

 1859 (1 l)aphnia, 1 DiaptomuSj 1 Estheria, 2 G^pris), and, 

 lastly (in Sept. 1861), a new Branchipus. 



In order to ascertain whether the ova deposited in captivity 

 would develop another year, 1 suggested to Mr. Denny that 

 in the summer he should decant the water and dry off the 

 mud without disturbing its surface. This he did by means 

 of a syphon, leaving the mud dry till the following spring, 

 in imitation of nature, when the glass jar was again filled. 

 The experiment was quite successful, most, if not all, of the 

 species reappearing. 



At the end of i8G0 I returned to England, and brought a 

 fresh supply of the mud, portions of which were given to 

 several gentlemen, who repeated the experiment, with similar 

 results. 



By alternating the seasons in the manner above described 

 the crop was renewed year by year, most of the species living 

 for two months, several for three months or more, then 

 depositing their ova and dying. Tliis was repeated at the 

 Leeds Philosophical Society's Museum for eight years ; and 

 it \\as only in the winter of 1836 that an accidental exposure 

 of the jar to a severe frost on the housetop destroyed them all. 

 Ann. cD Mag. N, Hint. Ser. 7. Vol, ii. 26 



