174 THE FRESH-WATER MUSSEL [CH. VI 



the alimentary canal of an Anodonta cygnea taken from 

 Busbridge Ponds, near Godalming, and dissected within 

 an hour of capture revealed carapaces and fragments of 

 limbs of minute Crustacea, shreds of epidermis of dicotyle- 

 donous leaves and of wood fibre, filaments of Spirogyra, 

 and enormous numbers of a spirilliform bacterium, as well 

 as the following 1 : numerous remains of Rotifers, Rhizo- 

 pods, etc., Sponge Spicules, Diatomacece of the following 

 species, Frigilaria capucina Desm., Cocconeis placentula 

 Ehrenb., C. pediculus Ehrenb., Navicula Brebissonii Kiitz, 

 N. eodlis (Ktitz), Grun., N. radiosa Klitz, Eunotia pecti- 

 nalis (Dillw.), Rabenh., Nitzschia palea (Ktitz), Sm., 

 N. acicularis (Kiitz), Sm., Pleurosigma attenuatum (Kiitz), 

 W. Sm., Diatoma elongatum Ag., Cymbella lanceolata 

 (Ehrenb.), Kirchn., C. cymbiformis (Kiitz), Breb., C. cistula 

 (Hempr.), Kirchn. var., maculata (Kiitz), Grun., Melosira 

 varians Ag. ; five species of Desmidiacece, viz. : Cos- 

 marium prcemorsum Breb., C. Turpinii Breb., C. botrytis 

 Menegh., C. granatum Breb., var. subgranatum Nordat. 

 and Staurastrum crenulatum (Nag.) Delp., and three 

 species of Protococcoidese, Scenedesmus quadricauda 

 (Turp.), Menegh., Pediastrum Boryanum (Turp.), Brel)., 

 and Dictyosphcerium Thunbergianum Nag. It is remark- 

 able that a large number of these Algse were found to 

 be in a fragmentary condition, probably as the result of 

 digestive changes undergone within the stomach or in- 

 testine. 



After entering the mouth the food is swept by 



1 Kindly identified by Prof, G, S. West of the Royal Agricultural 

 College, Cirencester. 



