ANODON. 
275 
sloping upwards, and forming an angle with the fore 
part of the shell. In M. cygneus the base slopes 
upwards; and M. incrassatus differs from them all 
by its large exserted ligament, superior roughness of 
the outside, and in having the posterior part, in a 
slope from the umbones to the base, incrassated. 
{Linn. Trans, xiii. 87.) 
The Abbe Dupuy divides the French species into 
sections, thus : — 
a. Cygnm. — - Shell very large, thin, with the mus- 
cular scars scars slightly marked. 
1. A. cygnsea. 
Ponderosa. — Shell large, very thick, especially 
in front, muscular scars deep. 
2. A. ponderosa, Dupuy ^ t. 1. £ 12 . — 3. A. 
Dupuyi, t. 17. £ 13. — 4. A. subponderosa, 
t. 17. £ 14. — 5. A. Rossmassleriana, t. 18. 
£ 14. 
7. Anatina. — Shell small, generally shorter and 
thinner than the preceding, with the muscular 
scars less deep. 
6. A. anatina, t. 19. f. 13, 14.; t. 20. f. 20.— 
7. A. piscinalis, t. 19. £ 17, 18. — 8. A. 
scaladiana, t. 19. f. 12. — 9. A. Rayii, t. 20. 
£ 22. — 10. A. coartata, t. 20. £ 21. — 11. 
A. Milletii, t. 21. f. 16. 
3. Hiantes — Shell middle size or small ; valves 
more gaping on the lower front edge than the 
preceding. 
12. A. Gratelupeana, t. 17. f. 22. 
T 2 
