Structural and Systematic Conchology: an Introduction to the Study of the Mollusca...

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The author, 1882 - Mollusks - 453 pages
 

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Page ii - Which strike ev'n eyes incurious ; but each moss, Each shell, each crawling insect, holds a rank Important in the plan of Him who framed This scale of beings ; holds a rank which lost Would break the chain, and leave behind a gap Which Nature's self would rue.
Page 273 - ... years for use in the Mississippi River have a capacity of over 1,000 cubic yards per hour. Dredging is also the operation of dragging the bottom of the sea in order to bring up oysters, or to procure shells, plants, and other objects for scientific observation. The oyster dredge is a light iron frame with a scraper like a narrow hoe on one side; and a suspending apparatus on the other. To the frame is attached a bag made of some kind of netting to receive the oysters. The dredges used by naturalists...
Page 60 - Shells are at once the attraction of the untutored savage, the delight of the refined artist, the wonder of the philosophic zoologist, and the most valued treasures of the geologist. They adorn the sands of seagirt isles and continents now; and they form the earliest "footprints of the sands of time
Page 127 - In these, the yelk undergoes partial division, and the blastoderm, formed upon one face of it by the smaller blastomeres, spreads gradually over the whole ovum, enclosing the larger and more slowly dividing blastomeres. The mantle makes its appearance as an elevated patch in the centre of the blastoderm, while the future arms appear as symmetrically disposed elevations of the periphery,, on each side of the mantle. Between these and the edge of the mantle, two longitudinal ridges mark the rudiments...
Page 276 - None of the shells were Miocene or of an older period. "This remarkable collection, of which not much more than one-half is known to conchologists, notwithstanding their assiduous labours, teaches us how much remains to be done before we can assume that the record of Marine Zoology is complete. Let us compare the vast expanse of the sea-bed in the North Atlantic with that small fringe of the coast on both sides of it which has yet been partially explored, and consider with reference to the dredging...
Page 16 - ... bivalves the embryonic shell forms the umbo of each valve ; it is often very unlike the after-growth, as in unio pictorum, cyclas henslowiana, and pecten pusio. In attached shells, like the oyster and anomia, the umbo frequently presents an exact imitation of the surface to which the young shell orignally adhered. Shells are composed of carbonate of lime, with a small proportion of animal matter.
Page 17 - Completely spherical pearls can only be formed loose in the muscles, or other soft parts of the animal. The Chinese obtain them artificially, by introducing into the living mussel foreign substances, such as pieces of mother-of-pearl fixed to wires, which thus become coated with a more brilliant material.
Page 280 - Some species inhabit stations subject to drying during a portion of the year, and careless observers have been deceived on finding them alive in their dried habitat, and have inferred they were bivalve land shells ! All the shells of this class burrow just beneath the surface of the mud, and are usually found in greatest abundance near the margin of the water, or where there is but little depth. This class embraces some species remarkable for their fragility, others equally remarkable for their minuteness....
Page 288 - Should the collector find it convenient to correspond with some other person similarly engaged, or should he desire to transmit a package of shells to some friend or to some public institution, a few suggestions relative to packing shells for transportation may be of use. Obtain a sufficiently strong box of suitable capacity ; on the bottom should be laid a thin bed of soft hay, or some other suitable elastic material. The larger shells (if such are to form a part of the contents of the package)...
Page 147 - March 7th, 1850, it was observed that he must have come out of his shell in the interval (as the paper had been discoloured, apparently in his attempt to get away) ; but finding escape impossible, had again retired, closing his aperture with the usual glistening film ; this led to his immersion in tepid water, and marvellous recovery. He is now (March 13th, 1850) alive and flourishing, and has sat for his portrait.

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