. Smithsonian miscellaneous collections . udinal axes subparallel to theaxial lobe of the dorsal test. As seen in the section (figure 1, plate96) the upper arm (1) is represented by a row of small round whitedots with a few oblique transverse segments on the left end, faint oblique lines that give a spiral appearance to thesection of the arm. The second exopodite (2) has about 26 obliquelytransverse segments and spiral structure indicated. The third(3) exopodite has a distinct spiral with about 24 oblique segments;the spiral structure is more pronounced in the fourth (4) and the
. Smithsonian miscellaneous collections . udinal axes subparallel to theaxial lobe of the dorsal test. As seen in the section (figure 1, plate96) the upper arm (1) is represented by a row of small round whitedots with a few oblique transverse segments on the left end, faint oblique lines that give a spiral appearance to thesection of the arm. The second exopodite (2) has about 26 obliquelytransverse segments and spiral structure indicated. The third(3) exopodite has a distinct spiral with about 24 oblique segments;the spiral structure is more pronounced in the fourth (4) and the30 segments are more strongly outlined and some are broader, but 4IO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 67 the spiral structure is preserved about midway of the length of thearm; the fifth (5) exopodite has about 40 segments indicated andthe section shows 16 or more long slender filaments a number ofwhich are connected directly to the segments of the arm, but thesection does not cut across the exact point of contact with the seg-. Fig. 17.—Diagrammatic outline of a dorsal view of a portion of a thoracicexopodite of Calymene. 1-9 = close coils of a spiral arm. 1-7 = bases (a)of seven branchial tubes (b) attached to dorsal side of the coils of the spiralarm. a = supporting base of branchial tube attached to spiral arm. b = bran-chial tube inserted in a at c. d = hollow interior of spiral arm of exopodite. ments of the arm in a manner to clearly indicate the character of theunion betwen them; this is found in the sixth (6) exopodite whichhas six filaments and portions of transverse spiral segments. Thecut is diagonally across the segments and brings into view the thick-ened sheaths of three segments with the point of insertion of the
Size: 1536px × 1627px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
