04 Crystals in the Intestines of Artemia Salina. 



purified coal oil. Though large quantities of photogen oils are 

 manufactured in this country, the foreign kinds are extensively 

 used. In 1857, seven hundred tons were imported, and the 

 imports are larger at present. 



CRYSTALS IN THE INTESTINES OF ARTEMIA 



SALINA. 



BY HENEY J. SLACK, F.G.S., 



Member of the Microscopical Society of London. 



The Artemia salina, or brine shrimp, is the most elegant of 

 British entomostraca ; but though well known to the professed 

 naturalist, it escapes the general observer from the peculiarities 

 of its mode of life. They sometimes occur in salt marshes, but 

 their favourite haunts are brine pans, in which sea-water is eva- 

 porated ; and when the solution reaches a strength that wtfuld 

 be fatal to most forms of marine zoology, the little brine shrimp 

 is singularly happy, and multiplies its species to an amazing 

 extent. The visitors to Lymington, in Hampshire, find it 

 abundantly in the tanks or reservoirs, called " clearers," to 

 which it often imparts a lively red tint, and it is found in equal 

 plenty in the salt works near Montpellier. Another locality is 

 Hayling Island, near Havant, on the Hampshire coast, and from 

 this place Mr. Burr brought the specimens which I have been 

 able to examine. The little creatures are about half an inch 

 long, of a beautiful pearly hue, much redder in some individuals 

 than in others. The head is rendered conspicuous by a pair of 

 prominent and exquisitely formed eyes, composed of many 

 lenses, like those of the dragon-fly, and standing upon trans- 

 parent stalks, which facilitate the study of their mechanism 

 under various microscopic powers from fifty to three hundred. 

 The head is further adorned by large flat two-jointed cephalic 

 horns, and the mouth is furnished with two mandibles, the ter- 

 minations of which exhibit thousands of minute teeth, which 

 require a magnification of 400 or 500 linear to be distinctly 

 seen. The tlmrax consists, according to Laird, of eleven 

 segments, to each of which is attached a. pair of branchial feet, 

 lobed in a peculiar way, and adorned with bristles, beautifully 

 toothed and branched. The effect of the eleven pair of bran- 

 chial feet is to give an appearance of considerable breadth to 



the thoracic pari of the animal, and make the abdomen, which 



is composed of six Blender joints, ending in two small caudal 

 appendages, look like a long flexible tail, and it acts like one 

 when the creature The motions are incessant. Seen 



