29 
Fam. 3. Saxicavida?. 
Foot small, cylindrical, inferior, byssiferous. Gills two on each 
side. Lips small. Siphons moderate. Shell solid. Ilinge-teeth 
rudimentary. Cartilage thick, marginal. 
1. Saxicava. 
1. S. rugosa, t. 339. f. 1, t. 347. f. 7, 9, t. 372. f. 4. 
2. S. rubra, t. 347- f. 8. 
2. Panomya. 
1. P. norvegica, t. 346. f. 1. 
Fam. 4. Pholadomyadcs. 
Foot short, compressed, with a small bifurcate pedal appendage 
behind. Siphons united. Pedal opening small. Gills two on each 
side, thick, united behind the body. Shell oblong, gaping at each 
end. Hinge-teeth rudimentary or none. Cartilage marginal, ex- 
ternal. 
1. Pholadomya. 
Fam. 5. Solenidce. 
Foot very large, clavate or truncated in front, not byssiferous. 
Pedal opening anterior. Gills two on each side. Shell cylindrical 
or oblong, gaping at each end. Hinge-teeth distinct. Cartilage 
very large, marginal, on a distinct fulcrum. Living sunk in the 
sand. (See Ann. fy Mag. N. H. xiv. 1854, 23.) 
* Cardinal teeth \ '1. Siphon produced, united. Siphonal muscles 
moderate. Siphonal inflection deep, truncated. 
1. SoLEN. 
1. S. vagina, t. 337. f. L 2, 3, t. 343. f. 1. 
** Cardinal teeth 2 * 3. Shell rounded at each end. 
t Siphons moderate, separate. Siphonal muscles small. Siphonal 
inflection small, truncated. 
2. Ensis. 
1. E. Siliqua, t. 342. f. 2, 3, 4, t. 343. f. 2, 3, 4 (fig. 11). 
2. E. pellucidus, t. 344. f. 5. 
Fig. 11 . — Ensis Siliqua. 
Valves forced open. Mantle divided as far as the ventral foramen, 
to show the foot. 
