LIMID^. 287 



the same nest or case ; but when thej^ become adult each indi- 

 vidual has a house of its own. This remarkable construction is 

 funnel-shaped, with the larger end contracted, and sufficiently 

 wide to admit of the Lima moving freely up and down, but not 

 turning around in it. Here it lives, secure from prowling fish 

 and crabs. The case is lined inside with a closelj^-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 nest of snakes, but afterwards they are withdrawn and become 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 verj'' easily broken off, and that they 

 seemed to live many hours after being detached from the bod}^ 

 wriggling about like so many worms. A remarkable peculiarit}'^ 

 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 Jeffreys, Br-it. Conch, 



LiMATULA, S. Wood, 1839. Valves equilateral, radial ribs only 

 developed in the middle of the shell. 8 sp. Greenland — 

 Britain. Fossil. Miocene — ; Europe, iv. fti^ZZaiJa, Born (cxxxii, 

 93). 



LiM^A,Bronn, 1831, Hinge minutely toothed. L. strigillata, 

 Brocchi. Fossil, 4 sp. Lias — Pliocene. The recent Lzwasa? 

 Sarsii, Loven (cxxxii, 94),]N"orway (= L, crassa of the JEgean ?), 

 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. L. 

 scabra, Born (cxxxii, 95). 



MANTELLUM, Bolten, 1798, Shell thin, ventrioose, oblique, 



