180 Our Oysters' Food. 



Food. As to this, the contents of the alimentary canal 

 presents quite an assortment of substances. The water 

 currents simultaneously carry in sandy mud and extraneous 

 matter along with the nutrient particles. These last are 

 chiefly diatom and desmid-plants, seaweed spores, infusoria, 

 foraminifera, along with minute larvae of hydroids, worms, 

 mollusks and Crustacea. Most of these are so broken up as to 

 be difficult to determine, but the diatoms and foraminifera 

 with their hard silicious crusts are more readily identified. 

 Such at least was the case in our examinations of oysters from 

 Hadleigh Bay layings, diatoms being a prominent feature 

 under the microscope. Indeed, nigh 60 years ago the Rev. J. 

 B. Beade* found the oyster's stomach to contain (besides other 

 material) close on 20 different species of diatoms. Many of 

 these latter are forms of common occurrence in the Thames 

 estuary. 



As mentioned before, p. 15, in connection with Whitstable 

 Bay and its matchless fattening grounds, our Thames mud flats 

 swarm with lowly plant and animal organisms, fit food for the 

 oyster family, and the sea water and shallow banks to the 

 estuarine limits receive their quota of brackish water forms 

 every ebb tide. The Mersea and Blackwater shores, Shenstone and 

 Benham have shown, are equally fruitful of oyster food.f Sorby 

 even goes further, and essays io prove in the case of Pagelsham 

 and Brightlingsea that the variance in the growth and flavour 

 of the oysters at those places bear relation to the amount of 

 diatoms in the former and infusoria in the latter. J Previously 

 he had pointed out the most extraordinary abundance of minor 

 life in the Swale, Queenborough, the Medway generally, as 

 well as the Lower Thames reaches. Shrubsole, a shrewd 

 naturalist (formerly resident at Sheerness), regarded the 

 oyster food of the Medway grounds as mostly diatomaceous ; 



* " On the animals of the chalk still found in a living state in the stomach of the 

 oyster." Trans. Micros. Soc., Vol. II., 1849 (read Dec., 1844). 



t Essex Nat. III. (1889). J Essex Nat. X. (1897). Rochester Naturalist, Oct. 1883. 



