10 
p. 377. Mont. Test. Brit., vol. 1, p. 99. L. Y. Flem’ 
Brit. An., p. 464. The separate valves are found thinly 
scattered along all our coasts. 
L. HIANS. Mactra H. Mont. Test. Brit., vol. 1, p. 101. 
Mya oblonga, Turt. Lin. L. H. Flem. Brit. An., p. 46 
Rare or local. Montagu found it not uncommon in the 
river between Truro and Falmouth. 
MACTRA. 
GENERIC CHARACTER: Shell transverse, the side* 
unequal; the form subtriangular, gaping very little at the 
sides ; beaks prominent. One compressed, grooved, car- 
dinal tooth in each valve, with an adjoining pH projecting 
inwards ; two compressed, entering, lateral teeth, near the 
liino-e. Ligament internal, inserted in the cardinal pits. 
* M. SOLIDA. Turt. Lin. Pen. Brit. Zo., vol. 4, pi. oO, 
fig 43 Stew. Elern., vol. 2, p. 377. Mont. Test. Brit., 
vol’. 1, p. 92- Flem. Brit. An., p. 26. Abundant along 
our southern coast. T e. • a * 
On the beach at Helford, near Falmouth, I obtained 
complete shell and two separate valves of, what must b 
considered, a separate species or a variety of the above, as 
future research shall determine. It is of the ordinary size 
and appearance of the milk white specimens of M. Solida, 
but from each umbo proceeds to the posterior margin a deep 
channel, which forms an indentation at their place ot meeting- 
I had no opportunity of examining the animal. 
* M. TRUNCATA. M. Subtruncata. Mont. Test. Brit-, 
vol 1 D. 93. M. Stultorum. Pen. Brit. Zo., vol. 4, pi- 
52 fi“'. 42. Stew. Elem., vol. 2, p. 377. M. T. Flem- 
Brit °An., p. 427. I have found it larger than the las 1 
named species; frequenting similar situations, but less 
abundant. 
M. GLAUCA. Mont. Test. Brit., vol. 2, p. o71. Fie 
Brit. An., p. 428. Found by Miss Pocock on Halesands, 
* M. ' STULTORUM. Turt. Lin. Tellina Radiata Of 
Montagu’s opinion) Pen. Brit. Zo., vol. 4, pi. 49, fig. ‘ 
M. S. Mont. Test.- Brit., vol. 1, p. 94. Stew. Elm. vol. 
p. 370. Flem. Brit. An., p. 427. Not common on tB? 
eastern shores; but occurring on the north and sou 
coasts, and at Pentuan in abundance. 
M. DEALBATA. Mont. Test. Brit., vol. 1, p. 95. Field 
Brit. An., p. 428. Scarce. 
M. MINUTISSIMA. Goodallia M. Flem. Brit. A ■> 
p. 429. 
AMPHIDESMA. s 
GENERIC CHARACTER: The shell transverse, side 
unequal, rounded, sometimes gaping a little ; hinge ^ 
