. A contribution to American thalassography : Three cruises of the United States Coast and geodetic survey steamer "Blake", in the gulf of Mexico, in the Caribbean sea, and along the Atlantic coast of the United States, from 1877 to 1880. Blake (Steamer); Marine animals -- Atlantic Ocean; Marine sediments. THREE CRUISES OF THE " ; the aperture with the outside of the preceding whorl. This notch permits the refuse matters discharged from the anal open- ing to escape outside of the shell without fouling the water which is used by the gills in respiration. These mollusks
. A contribution to American thalassography : Three cruises of the United States Coast and geodetic survey steamer "Blake", in the gulf of Mexico, in the Caribbean sea, and along the Atlantic coast of the United States, from 1877 to 1880. Blake (Steamer); Marine animals -- Atlantic Ocean; Marine sediments. THREE CRUISES OF THE " ; the aperture with the outside of the preceding whorl. This notch permits the refuse matters discharged from the anal open- ing to escape outside of the shell without fouling the water which is used by the gills in respiration. These mollusks are found at all depths, are animal feeders, and some of them are provided with barbed hollow teeth, having a duct to which a gland supplies a poisonous substance; such an apparatus is even more fully and generally developed in the related group of Conidse, few of Avhich reach any great depth. Among those Pleurotomidse which would attract especial at- tention is the exquisite Pleurotoma (Ancistrosyrinx) elegans (Fig. 282), one of the most beautiful gems of the sea. It grows to an inch and a half in length, and is of a light straw color; the posterior surface of the whorls is con- cave and carinated, the cari- nse being delicately fringed with sharp triangular points ; it has a deep notch, which in perfect specimens has a raised margin. This species descends to eight hundred fathoms, and has been found alive at Bar- b a d o s in seventy - three fathoms. Its fossil allies extend as far back as the eocene. Pleurotoma subgrundifera Dall (Fig. 283) is a form which, in- stead of having the margin turned toward the tip of the spire, has the sharp keel bent in the opposite direction toward the canal, like the edge of an umbrella. Another pretty species, dredged in deep water both by the " Blake " and the " Challen- ger," is Pleurotoma Blakeana ; and still another, short and stout, with delicate reticulate sculpture, has also been obtained by the Fish Commission, th
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Keywords: ., bookauthoruscoasta, bookcentury1800, bookdecade1880, bookyear1888
