Crystals in the Intestines of Artemia Salina. 97 



and another such as would result from applying a right angled 

 triangle to each of the smaller ends of an oblong figure. Both 

 of these were exceedingly small, and required the one-twentieth 

 for their adequate display. Referring again to plate 8 of the 

 Micrograjphic Dictionary, the reader will see, in fig. 2 a, how a 

 hexagon may be formed by the coalescence of two rhombs, and 

 two half rhombs, or triangles, of uric acid. I looked in vain 

 for perfect rhombs in my specimens, but Professor Tuson, to 

 whom I gave some of the second batch of Artemia, discovered 

 some in his. 



It would be absurd to place much faith in generalizations 

 drawn from a few observations, but it is curious that my first 

 supply of brine shrimps, containing the aigrettes, lived for 

 some weeks in confinement, and mostly perished through micro- 

 scopic examination, while the second supply, containing the 

 amorphous lumps, died off very fast. Does the amorphous 

 condition indicate a rapid deposition, arising from an excess of 

 uric acid incompatible with the little animal's well being ? 

 Living far away from the Hampshire brine pans, I cannot 

 expect to unravel the difficulty ; but where there are brine 

 pans, there are no doubt " Intellectual Observers," and I hope 

 some of your readers will give to this curious question the 

 attention it deserves. I should also like to know whether 

 crystalline forms are common in the intestines of other marine 

 entomostraca, and whether their appearance at all, or only 

 their appearance in excess, is a symptom of bad health. I 

 cannot believe that concretions, relatively large in proportion 

 to the intestine^ can be productive of comfort, and some of them 

 were so stuffed up with angular particles as to suggest the idea 

 that a visit from Dr. Civiale, with an apparatus adapted to 

 microscopic lithotrity, would have been a desirable event. 



On the 19th July I had only one Artemia left, and it was 

 still very lively ; but on looking attentively into the bottle it 

 appeared to have acquired a famous long tail, which it swished 

 about as it went. A pocket lens explained this appearance, 

 and showed nine cylindrical pellets of foecal matter, equidistant 

 from each other, and held together by some transparent mate- 

 rial. The pellets proved, on examination, to be full of amor- 

 phous particles, but I could not succeed in making out how 

 they were strung together, whether by a thin membrane carried 

 away from the intestine, or by a mucous secretion. I relieved the 

 Artemia of this strange appendage, and it seemed none the worse 

 after being replaced in its bottle. 



I have called the deposits uric acid, but I had not enough 

 of the material for definitive experiments. Professor Miller 

 states, in his Elements of Chemistry, that " uric acid crystallizes 

 in rhombic tables, the outlines of which are frequently rounded ; 



