On an Aquarium for Marine Animals and Plants. 268 



R. littorea, Delle Chiaje, is an apocryphal British species ; and 

 the so-called R. eximia is an undoubted Chemnitzia allied to 

 C. excavata ; 1 have described the shell, the animal being undis- 

 covered, under the title of C Barleei. The R» ulvce and its 

 varieties have appeared in the 'Annals/ N. S. vol. v. p. 358. I 

 cannot speak of the R. anatina and R. ventrosa, not having met 

 with them ahve. The account of the animal of R.fulgida is 

 published in the 'British Mollusca' from my notes; it differs 

 much in the proportionate dimensions of its organs, but there 

 is no sufficient generic variation to remove it from this genus. 

 At Exmouth it is abundant on the algae of the half-tide littoral 

 levels. The Turbo subumbilicatus of Montagu is still in obscu- 

 rity ; it is perhaps a variety of one of the species of the estu- 

 aries, and if it could be identified, its position would probably 

 be in this genus. I mention the Jeffreysia diaphana and /. opa- 

 Una, because they have recently been styled Rissoa; they ap- 

 pear from several characters to form the passage to the Chem- 

 nitzia. I think 1 have now named every Rissoa, 



I conclude this still imperfect monograph by calling on the 

 naturalists of this branch of science to make it more complete, 

 by searching in their respective localities after the animals which 

 continue to elude our view ; as without the inhabitants of shells, 

 the essential part of this portion of nature is hidden from us. 

 Conchology as a science is little better than the toy of the shell- 

 fancier; we can only admit that these persistent forms, inde- 

 pendent of the animal, are useful as objects of comparison with 

 some of the antediluvian relics of our globe, as they prove that 

 nature, at least a part of it, existed in the palseontozoic epochs 

 as at the present time. 



I am. Gentlemen, your most obedient servant, 



William Clark. 



XXIV. — On keeping Marine Animals and Plants alive in un- 

 changed Sea-water. By P. H. Gosse, A.L.S. 



To the Editors of the Annals of Natural History. 



Gentlemen, 



In a recent Number of ' Chambers^ Edinburgh Journal ' (July 

 1852) a paper has just been pointed out to me, on maintaining 

 the balance between animal and vegetable life in an aquarium. 

 Mr. Warington, whose experiments are there alluded to, has 



