The royal natural history . 43° Thecidium mcditerraneum. A, Nat. size; B,Section through the shell (magnified). calcareous framework nowhere rises freely from the lid, with which it is connectedby a calcareous network. In the section (B) given in the illustration we see in thedorsal valve the depression for the hinge on which the valve rotates. The shell isopened by the muscles (b) which run from the bottom of the ventral valve to aprocess directed backward in the dorsal valve behind the hinge. It is closed bythe muscles marked a, which lie in front of the hinge. The shells of T
The royal natural history . 43° Thecidium mcditerraneum. A, Nat. size; B,Section through the shell (magnified). calcareous framework nowhere rises freely from the lid, with which it is connectedby a calcareous network. In the section (B) given in the illustration we see in thedorsal valve the depression for the hinge on which the valve rotates. The shell isopened by the muscles (b) which run from the bottom of the ventral valve to aprocess directed backward in the dorsal valve behind the hinge. It is closed bythe muscles marked a, which lie in front of the hinge. The shells of Thecidium become attached to submarine objects, andare brought up in considerable numbers bythe nets of the coral - fishers between theGulf of Bona and Cape Rosa, from a depthof from forty to fifty fathoms. The numberof specimens of Terebratula is small ascompared with that of Thecidium, twentyto thirty specimens of the latter beingoften found together. When first caught,Thecidium opens its valves very wide, butwhen isolated and placed in smal
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Keywords: ., bookcentury1800, booksubjectnaturalhistory, booksubjectzoology
