NEW EDIBLE ROOTS. 177 



years'? — that many of the oysters will die a natural death, and that many 

 more will be used as food by thousands of voracious marine animals in the 

 interim, is a certainty ; but we should not forget that there is a probability 

 of whole masses being carried away from other causes. What may now 

 appear likely to yield a revenue of many hundred thousands, may not 

 produce more than a few thousands at the end of five or six years. It is 

 time, now that the Emperor of France has acted upon the suggestion of 

 a French naturalist, and thereby increased the production of the edible 

 oysters of France, that the Ceylon Government should treat the pearl 

 oysters with more care and consideration than it has hitherto done, so that 

 the profit derived from this source may become a permanent or less fluctu- 

 ating revenue, and that the plan proposed by their naturalists should be 

 at least fairly tried, even on a small scale, before any decision adverse to it 

 be adopted. 



I have not in this paper detailed some very hiteresting discoveries made 

 since my last report on the anatomy and physiology of the pearl oysters, 

 believing that they are better fitted for a treatise on the subject, than to be 

 embodied in a report to the Ceylon Government, which must necessarily 

 be written in a popular form. However, as this report may, like the 

 preceding ones, fall in the hands of scientific men, I shall merely mention 

 here, that Monsieur Humbert, a Swiss zoologist, has, by his own micros- 

 copic observations at the last pearl fishery, corroborated all I have stated 

 about the ovaria or genital glands and their contents ; and that he has 

 discovered in addition to the filaria and circaria, three other parasitical 

 worms infesting the viscera and other parts of the pearl oyster. We both 

 agree that these worms play an important part in the formation of pearls ; 

 and it may yet be found possible to infect oysters in other beds with these 

 gems. The nucleus of an American pearl drawn by Mobius, is nearly of 

 the same form as the circaria found in the pearl oysters of Ceylon. It will 

 be curious to ascertain if the oysters in the Tinnevelly banks have the 

 same species of worms as those found in the oysters on the banks at 

 Arrippo. 



Trincomalie, Ceylon, 1859. 



NEW EDIBLE ROOTS. 



BY THE EDITOR. 



It is surprising how little we have experimentalised in this country upon 

 new edible roots, which might come in as useful aids to the potato for food 

 purposes. But two or three attempts are all that we can call to mind ; and 

 yet the field of research is a wide and a promising one, especially now that 

 our trade with foreign countries, and quick steam navigation, places so 

 many tuberous-rooted plants within our reach for trial and cultivation. 

 The attempt to introduce some one that might prove suitable to our climate, 



