446 



Entomostraca (Water-Fleas). 



being from W. to S., as no doubt the substantially-built bouse 

 and stables to the W. of it saved the trees, yet those left 

 standing were such as would have received no protection if the 

 force had been either direct, or if it had rotated from S. to W. 



The fall of 22°"6 of temperature in two hours at the High- 

 field House Observatory (twenty miles away) was no doubt 

 owing to this gale. 



A number of photographs were taken along the path of 

 the gale with " Dr. Hill Norris's Dry Plates." I name this as 

 these plates had previously travelled with me to Spain in July 

 I860, and although this box was only opened in May 1862, 

 they were in excellent condition. 



ENTOMOSTRACA* (WATER-FLEAS). 



BY G. S. 



BEADY, M.E.C.S. 



Among the many groups of minute organisms to which micro- 

 scopic observers are accustomed to devote then attention, there 

 is scarcely any that is more calculated to interest the student 

 inquiring into the curiosities of animal life, or to fascinate one 

 who seeks only for amusement from the employment of his 

 microscope, than that which embraces the strange beings 

 known as Entomostraca. They are objects too particularly 

 easy of access to almost everyone ; for wherever water is they 

 are abundant. It is, indeed, scarcely possible to dip a net into 

 any weedy pool without bringing out of it some examples of 

 the tribe ; though probably in this case only common species, 

 such as Oyclops quadricomis or Ohydorus splatsrlcus. These two 

 animals must be known by sight, if not by name, to every one 

 who has examined microscopically a drop of water from a stag- 

 nant pond. And not only in fresh water do Entomostraca 

 abound ; they exist, likewise, in prodigious numbers in the sea, in 

 brackish waters, and even in the concentrated brine of salt mines. 

 Many species are parasitic on the skin, gills, and eyes of fishes, 

 and some are found living even in the interior of zoophytes, 

 etc. Though thus almost ubiquitous in habitat, they are seldom 

 found in rapidly-running streams — delighting rather in the clear, 

 still and sweet waters of lakes and largo ponds : these, when 



* The class Crustacea is divided as follows: — PodophthaLna, or stalk-eyed 

 Crustacea (crabs, lobsters, etc.) ; Edriophthalma, or sessilc-cyed Crnatacea (sand- 

 hoppers, etc.) ; Entomostraca (water-fleas, fish-lice, etc.) liy some authors the 

 Podosomata, or sea-spiders, and the Cirripedia (Barnacles), are included amongst 

 Crustacea. The Rotifera have also been considered to belong properly to this 

 class, but probably with less propriety. Mr. Gosse, who has paid great attention 

 to them, thinks that they have closer aflinity with the insects. 



