LIMID. 287 
the same nest or case; but when they become adult each indi- 
vidual has a house of its own. This remarkable construction is 
funnel-shaped, with the larger end contracted, and suftliciently 
wide to admit of the Lima moving freely up and down, but not 
turning around init. Here it lives, secure from prowling fish 
and crabs. The case is lined inside with a closely-woven net of 
byssal threads, plastered over with slime or excrement. This 
smooth and soft lining contains a quantity of Diatom-cells, and 
yields a rich harvest to those who collect these exquisite organ- 
isms for microscopic examination. When the Lima is first taken 
out of its case and put into a basin of sea-water, it is exceedingly 
active and restless, or else gracefully careering about, with its 
long and thick fringe of filaments trailing behind it. In the 
course of a few minutes it seems to get tired or reconciled to its 
prison; and it then lies on its back, the valves of the shell 
expanded, and reposes on its own soft, luxurious cushion. The 
filaments at first curl and entwine round one another, a perfect 
nest of snakes, but afterwards they are withdrawn and become 
contracted, a circular inner row, like a coronet, surrounds the 
slowly flapping gills; and the outer rows fold over on each side 
and form a sort of chevaux de frise. Dr. Landsborough supposed 
that these filaments were useful to the Lima in catching its prey. 
He observed that they were very easily broken off, and that they 
seemed to live many hours after being detached from the body, 
_wriggling about like so many worms. <A remarkable peculiarity 
of Lima consists in the tenacious grasp of its tentacles ; some- 
times when my finger touched the animal, it was rapidly seized 
by the tentacles, as by those of an Actinia, and so firmly that I 
have dragged the Lima round the tank. It seldom let go its 
hold till the tentacles were torn away, or (as I believe) volun- 
tarily thrown off by the animal. The tentacles so detached still 
adhere closely to the object they have grasped, their free ends 
twisting about as if conscious of life, and they are with difficulty 
taken off.”—Dr. J. Gwyn Jeerreys, Brit. Conch. 
LIMATULA, 8S. Wood, 1839. Valves equilateral, radial ribs only 
developed in the middle of the shell. 8 sp. Greenland— 
Britain. Fossil. Miocene—; Europe. JZ. bullata, Born (exxxii, 
93). 
LiM#A, Bronn, 1831. Hinge minutely toothed. JL. strigillata, 
Broechi. Fossil, 4 sp. Lias—Pliocene. The recent Limezxa? 
Sarsii, Lovén (exxxii, 94), Norway (— L. crassa of the #igean ?), 
has the mantle-border plain. Some of the larger recent species 
have obscure lateral teeth. 
CTENOIDES, Klein, 1753. Shell thin, subequilateral ; sculpture 
radiating from the longitudinal centre-line of the valve. JL. 
scabra, Born (exxxii, 95). 
MANTELLUM, Bolten, 1798. Shell thin, ventricose, oblique, 
