OF NORTHUMBERLAND AND DURHAM. 175 
Lowlights being found insufficient for their supply. The Mus- 
sels got on these occasions are kept alive in pools among the rocks, 
built round with loose stones. 
85. MODIOLA, Lamarck. 
* SMOOTH. 
1. M. vonearis, Flem. 
Mytilus modiolus, Mont. Test. Brit. 163. 
Var. Mytilus barbatus, Mont. Test. Brit. 161. 
From deep water, common. The variety is frequently found 
on rocky ground, near low-water mark. 
It is remarkable that the large form of J. vulgaris is always 
found with us in deep water, never approaching the shore, and 
even rare in a depth of 20 or 30 fathoms, while on the western 
coasts it is found frequently in shallow water, and even close to 
low-water mark. 
*k RIBBED AT BACH END (Lanistina, Gray). 
2. M. niora, Gray. 
Mytilus descrepans, large var., Mont. Test. Brit. Supp. 65, 
t. 26, f. 4. 
Modiola nigra, Thorpe Brit. Mar. Conch. 249, f. 58. 
From deep water, rare. Cullercoats—J. A. Whitburn.— 
Rev. G. OC. Abbes. Mr. Howse dredged it alive in 17 fathoms. 
Mr. King has also got it from the fishing boats. 
The animal of this species is transparent white, with the mar- 
gin of the cloak and siphon speckled with brown and opake 
white. 
3. M. pescrepans, JZont. 
Mytilus descrepans, Mont. Test. Brit. 169. 
At the roots of sea-weeds between tide-marks, common. Also 
in corallines from deeper water, where it attains a much larger size. 
The animal is white, and, assisted by its long strap-shaped 
foot, can move about pretty quickly ; but it generally prefers a 
stationary life, and forms for itself a kind of nest or case by 
stitching together the small sea-weeds or corallines with its 
byssal threads ; here it remains attached by its byssus awaiting 
the food that may come within its reach. 
