184 CATALOGUE OF THE MOLLUSOA 
From deepish water, rather rare. Cullercoats. Newbiggin. 
Fern Islands— A. H. Seaton Carew.—Wr. W. Backhouse. 
98. SYNDOSMYA, Recluz. 
1. S. auBa, Wood. 
Mactra Boysii, Mont. Test. Brit. 98, t. 3, f. 7. 
On sandy shores, not uncommon. Plentiful at Whitburn. 
2. S. prismatica, JZont. 
Ligula prismatica, Mont. Test. Brit. Supp. 23, t. 26, f. 3. 
In deepish water, frequent. Often found in the stomachs of 
haddocks. 
3. S. tenurs, Mont. 
Mactra tenuis, Mont. Test. Brit. 572, t. 17, f. 7. 
Rare, “Seaton. Mr. J. Backhouse.” —Hogg Nat. Hist. Stock. 
From the stomach of a duck shot at Holy Island—2J*. Chas. 
M. Adamson. 
Faminty. Mactriva, Fleming. 
99. SCROBICULARIA, Schumacher. 
1. S. prana, Da Costa. 
Mactra compressa, Mont. Test. Brit. 96. 
Within tide-marks, or a little beyond, on a muddy bottom, 
generally at the mouths of rivers, not rare. Jarrow Slake, &c. 
100. MACTRA, Linneus. 
1. M. sonmpa, Linn. 
Mactra solida, Mont. Test. Brit. 92. 
Var. Mactra truncata, Mont. Test. Brit. Supp. 34. 
On sandy shores, not common. The truncated variety, J. 
truncata, Mont., is frequent in the north of Northumberland. 
2. M. evirprica, Brown. 
Mactra elliptica, Brown Illust. Rec. Conch. 108, t. 41, f. 6. 
From deepish water, not uncommon. 
3. M. sustruncata, Da Costa. 
Mactra subtruncata, Mont. Test. Brit. 93. 
On sandy beaches, frequent. Two varieties occur. The more 
usual kind is thick, solid, and strongly wrinkled, but there is a 
