(; L Y ( I M E K 1 S. 



(iLVCIMKIil.- 



J.an 



Tc.<ta transverse oblonga, hivalvis, himusculosa, ccqui- 

 valvis, crassa, epidemiide nigra cornea induta ; 

 viargine cardinali edcntulo. Ligamentum maymim 

 externum fulcrum magnum affixum. Impressiones 

 mvsculares complcxi, pallii irregulariter integer. 



Shell transversely oblong, bivalve, bimuscular, equi- 

 valvo, thick, covered with a black, horny epidermis; 

 hinge margin toothless. Ligament largo, ex- 

 ternal. Muscular impressions complex, tliat of 

 the mantle irregularly entire. 



SvN. Ci/rtodaria, Daudin. 



The single species which composes this genus, presents 

 an assemblage of characters which make it dillicult to 

 determine its place. Having neither internal car- 

 tilaginous pit nor appendage, it certainly does not belong 

 to the genus Mija, with which it was formerly united. 

 Yet, as in Mi/a, Panopiea, ttc, the parts of the animal 

 not covered by the shell are provided with a wrinkled 

 coriaceous covering. It is a mollusc of littoral habits 

 and, as might be suggested by its appearance, belongs 

 to northern and arctic seas. In the general characters 

 of the shell it secni^, with Soleninit/a, to :i.pproacli the 

 liimily of ,%,/,, ,;-!„. 



Species 1. (]\[us, Sowerliv. ) 



Glycimekis silkjUA. Gil/, tcstd ohlotuji'i, crrif.'sa, 

 utrinque hianti, exttis epidermide crassa, nigra, 

 oblique rvgata. induta ; iniui> cidcared, irregulariter 

 incrassatd et laceratd ; latere postico breriituruld 

 margine dorsali semilunari ; medio cumpresso, 

 margine vcntrali rectimculo ; cardine eduniuld, 

 fulcra ligamentifero maxima. 



The sword Glycimeris. Shell oblong, thick, gaping 

 o!i both sides, covered outside with a tliick, black 

 cjiidermis, obliquely wrinkled ; calcareous within, 

 irregularly thickened and jagged ; posterior side 

 rather the shorter, dorsal margin semilunar ; 

 middle compressed, ventral margin rather straight ; 

 hinge toothless, ligamentiferous ftdcruni very 

 large. 



LAM.\i!f'K. Anim. sans Vert., vol. vi. p. CO. 



Mya picea, Wood. 



Hah. Arctic Coasts. 



The so-called Glycimeris arctica and Ghjelmeris 

 eilentula do not Ixdong to this genus;. The first is a 

 Panapa.,. 



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