. Echinoidea. Sea urchins. â ^i*?°. Fig. 5- Fia;. 6. 9. Tromikosoma Koehleri n. g., n. sp. PI. XI Figs, 2, 13. PI. XII. Figs. 22, 31, 41. PI. XIV. Figs. 12, 16, 19, 21, 23, 25, 28, 30. Of this species we have only one very large specimen, 180â¢" in diameter, from st. 36 (61' 50' N. Lat. 56° 21' W. L. 1435 fathoms, bottom temperature 2°), the Davis Strait. Unfortunately it is very badly preserved, so that the description cannot be complete, and no figure can be given of the whole animal. So many characters may, however, be distinguished in the animal before ns, that genus and species ca
. Echinoidea. Sea urchins. â ^i*?°. Fig. 5- Fia;. 6. 9. Tromikosoma Koehleri n. g., n. sp. PI. XI Figs, 2, 13. PI. XII. Figs. 22, 31, 41. PI. XIV. Figs. 12, 16, 19, 21, 23, 25, 28, 30. Of this species we have only one very large specimen, 180â¢" in diameter, from st. 36 (61' 50' N. Lat. 56° 21' W. L. 1435 fathoms, bottom temperature 2°), the Davis Strait. Unfortunately it is very badly preserved, so that the description cannot be complete, and no figure can be given of the whole animal. So many characters may, however, be distinguished in the animal before ns, that genus and species can be recognised with certaint)-. â With regard to the generic characters see above p. 64â65. The structure of the test cannot be described completely, as the whole actinal side is torn; the abactinal side, on the other hÃ¥nd, is whole, and permits an examination of the form of the piates (Figs. 5â6). The ambulacral areas (Fig. 5) are uncommonly broad, a little broader than the inter- ambulacral areas. The primary ambulacral piates are angularly bent, with their top turned towards the ambitus; the outer half is a litte narrower than the inner one. The secondar\' ambulacral piates are Piece of ambulacral and luterambulacral area of Tromiko- soma Koehleri {^li\. In the animal the boundaries between particularly well develojied, especially the outer one the piates are white, the piates of a bluish gray. , . , , â¢. , ,1 1 r .1 11 1 â ^ which reaches qnite to the edge of the ambulacral area. Near the apical area the inner accessory ambulacral plate reaches quite to the median line where it adjoins the point of the primary ambulacral plate from the opposite side. Thus the primary ambulacral piates of the same side are here quite separated. The pores of the accessory piates are situated near the boundary line between the piates, the pore of the primary ambulacral plate is placed about under that of the inner accessory plate. Also the interambulacral piates are angular
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1903
