310 . Dr. Maton’s and Mr. Racxert’s 
Habitat in rivis et stagnis, frequens. 
Testa interdum 3 poll. longa, 6 lata, subpellucida, ad cardinem ventricosa, 
rugosa, epidermide virescente aut nigricante induta, intus margaritacea. 
Differt a M. anatino quod multo major, tenuior, et sepius convexior. 
Varietas 8. 2 poll. longa, 3 lata, crassa, ponderosa, rudis, anterius declivis. 
Mytilus cygneus and anatinus frequently resemble 
each other so much, that it is with difficulty they are 
to be distinguished ; and there are also many shells 
which appear to differ from them in some respects, but 
we have never found the variation sufficient to enable 
us to form a specific character upon it. : 
10. 
anatinus. M. testa ovali, compressiuscula, fragilissima,” E artic 
t. 9. A. f. 1. membranaceo, umbonibus decorticatis. Linn. Fauna 
Suecica, n. 92158. Syst, Nat. p. 1158. n. 258." - Linn. 
Gmel. p. 3355. 
Lister Anim. Angl. t. 2. B 29. 
Conch. t. 153. f. 8. 
Petiver Gaz. t. 93. f. 8. 
Gualt. Test. t. 7. f. E. 
— App. ty 1. fe 9. 
D' Argenv. Conch. t. 31. F 10. mL dues B | E: j 
Pennant Brit. Zool. t, 68. f. 79. 
Da Costa Brit. Conch. p. 215. 
 Schröt. Flussconch. tif, 3. 
Pulteney in Hutch. Dorset. p. 88.1.19... 6. — 
- Donovan Brit. Shells, t. 113. 
Monta, su Test: Brit. p. 17 lo 
B. Lister Conch. t. 154. f. D2) a 9999 Le 
t.3.A. f.4. Montagu Test. Brit. p. 172. M. Avonensis. 
Haliiat in aquis dulcibes; frequens. - 
Tesía interdum 2 poll, longa, 34 lata, epidermide etl fears, rugis 
transversis 
