Preliminary Report on the Ec̄hini

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Museum, 1898 - Echinodermata - 18 pages
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Page 85 - This species is readily distinguished from the other species of the genus by its proportionally greater length, the lateral flattening of the test, and the pointed anal rostrum. The tuberculation is also closer, and the primary spines
Page 72 - We can well imagine an equatorial current taking during Miocene and Eocene periods the young of the Echini flourishing in the Crag and in the Mediterranean, and in the southern extension of that fauna perhaps only from the Cape Verd Islands, and bringing them to the shores of Northern South America or into the Caribbean Sea.
Page 87 - confluence of the posterior ambulacra along the median line for nearly half their length, the great width of the posterior extremity of the test, the large and uniform size of the posterior ambulacral plates on the actinal side of the test, as well as the small size of the actinal plastron.
Page 81 - of the test are covered by small secondaries and miliaries; this tuberculation is closer than in any other species of the genus; the posterior extremity is more vertically truncated, and the anal groove not so pronounced as in H. fulva. The anal system is pyriform, its greatest diameter being transverse, as in H.
Page 71 - USN, Commanding. XXIII. Preliminary Report on the Echini. By Alexander Agassiz. The following brief descriptions, accompanied with figures of the more interesting species, collected during the " Albatross " Expedition of 1891, are published to prevent possible confusion in the names adopted for the new species of sea-urchins, which will appear on the Plates preparing for the final
Page 75 - The genus is marked by the great size of the genital and ocular plates of the apical system ; by the width of the interambulacral area, by the peculiar linear arrangement of the large interambulacral miliaries along the median line parallel with the horizontal sutures of the upper interambulacral plates. The
Page 77 - it has like it an extensive geographical range, but in comparatively deeper water. The largest specimens collected measured 201 mm. in diameter. The test is marked for the great width of the ambulacral system at the ambitus, which is nearly as wide as the adjoining interambulacral system. The large primary
Page 83 - Plate X. A number of specimens in excellent condition were dredged from the two localities at which this species was procured. The test of this species is thinner than in C. Loveni, but somewhat thicker than in C. vesica. A few of the specimens came up which had preserved their shape, so we are able to give figures
Page 79 - tremity does not pass, as in E. cuneata, into the anterior ambulacral groove. The actinal system is protected by five large plates. Station No. 3398, off Galera Point, in 1573 fathoms. " " 3399, off Galera Point, in 1740 fathoms. " " 3415, off Acapulco, in 1879 fathoms. Urechinus giganteus A.
Page 71 - a wide distribution, and that in a comparatively short time. "While undoubtedly many of the species of Echini have no pelagic Plutei, and are so to speak viviparous, or carry their young for a considerable period, yet we should remember that young Echini, even after they have