190 CATALOGUE OF THE MOLLUSCA 
The foot is large, subtriangular, and strongly kneed or angu- 
lated behind. It is protruded from the longer end of the shell, 
which in this genus is anterior. We have not been able to de- 
tect any siphons. Professor Lovén was the first to notice that 
this species, which is the MJesodesma exiguwm of his “ Index,” 
has an ossicle. By carefully opening some of our specimens we 
have also observed it. It appears to be a calcification of the 
lower part of the hgament, which is very easily detached, and 
is generally wanting in dead shells. We have not found the 
same process in the following species. 
2. M. supstriata, Mont. 
Ligula substriata, Mont. Test. Brit. Supp. 25. 
Taken abundantly by Mr. R. Howse, on the spines of Spa- 
tangus purpureus, from 60 fathoms water, 50 miles off the coast 
of Durham. 
Mr. Howse’s observations on the animal of this species agree 
with ours on J. bidentata, as to the shape and position of the 
foot, and the apparent absence of siphons. All the animals of 
this family appear to attach themselves by a byssus. 
3. M. rerrvuernosa, Wont. 
Mya ferruginosa, Mont. Test. Brit. Supp. 22, t. 26, f. 2. 
Under stones among the rocks at Cullercoats, and in sand, rare. 
Famity. ANATINIDA, Cray. - 
109. NEAERA, Gray. 
1. N. cusprpata, Olivi. 
Thracia brevirostra, Brown Illust. Rec. Conch, 110, t. 44, 
f. 11—14, 
First noticed on this coast by the Rev. W. Mark, who got two 
individuals from the stomachs of haddocks. From a fishing 
boat, Cullercoats (one specimen).—A. H. Mr. R. Howse has got 
one or two specimens from haddocks at Whitburn. 
110. CORBULA, Bruguiere. 
1. C. arppa, Olive. 
Mya inequivalvis, Mont. Test. Brit. 38. 
Corbula nucleus, Lam. Anim. s. Vert, 2nd Hd., vi. 139. 
