. The sea-beach at ebb-tide : a guide to the study of the seaweeds and the lower animal life found between tidemarks . ocking teeth, which project from the hinge. Theopening and shutting of the valves is controlled by the adductormuscles of the animal, by thelii/<iiii elastic pad of rubber-like appear-ance which is lodged just with-in the hinge, and is compressedwhen the valves are closed to-gether. Thus, when the valvesare closed, there is always a strainupon the adductor to overcomethe elastic resistance of the car- T> TV The interior rharartrnstirs nf a ]ic)ii-y|n«l tilage. When a pel
. The sea-beach at ebb-tide : a guide to the study of the seaweeds and the lower animal life found between tidemarks . ocking teeth, which project from the hinge. Theopening and shutting of the valves is controlled by the adductormuscles of the animal, by thelii/<iiii elastic pad of rubber-like appear-ance which is lodged just with-in the hinge, and is compressedwhen the valves are closed to-gether. Thus, when the valvesare closed, there is always a strainupon the adductor to overcomethe elastic resistance of the car- T> TV The interior rharartrnstirs nf a ]ic)ii-y|n«l tilage. When a pelecypod dies siu-n. Left \-ai\- ..... • r. «»*,/,//./, i,,-oa,ith of si^ii: «.«»., anterior,cles is released, the valves gape -^\- ^:^^^^^., OT)GD (»., lunult ; H, iinilio: i; rarilinal ti-ith; n. /., ail- trrior lali-ral ; //. I., posterior lateral t. The summit or apex of thevalve is called the unibo, or l>< <ik. It is usually twisted to someextent, and in certain forms develops a suggestive spiral beaks of the valves are the points where the shell-growthbegins, the secretion of calcareous matter being made by the man-tle margin and deposited about the edges of the valves; thegrowth is therefore constantly away from the umbones. The umbones usually point forward. In many species theytouch each other over the hinge-margin or approximate veryclosely; in other species the hinge-margin is very wide and thebeaks are comparatively far apart. The hinge-margin, lying adja-cent to the uniliones, is known as the ilorwil ninn/hi of the shell, incontradistinction to the rn<ir</in. opposite the <infi ri<»- ii/nn/iii is the Ironl edge and the jinxfi rinr ii/nn/iii thehinder edge of the shells, through which the siphons may project. When the umbones are about central in respect to the po
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmarinea, bookyear1901
