CROMYATRACTUS n. gen.
Haeckel, 1887a, p. 334
Type species: Cromyatractus tetraphractus Haeckel(SD, Chediya,1959, p.112)
Remarks on type species: [Campbell, 1954, p.D70 considers Cromyatractus Haeckel, 1887a, to be an objective synonym of Caryodoras Haeckel, 1881a. He designates Cromyatractus tetraphractus Haeckel, 1887a as the type species of Caryodoras and only by inference of Cromyatractus. However, this seems inappropriate since no species are known to have been assigned to Caryodoras. Therefore, we consider the type species designation of Cromyatractus tetraphractus Haeckel, 1887a, p.335, pl.15, fig.3, x300 to date from Chediya, 1959, p.112.]
Description: Druppulida with four or more concentric shells (two medullary shells and two or more cortical shells), in the main axis with two large opposite polar spines of equal size and similar form.
Remarks: The genus Cromyatractus is very nearly allied to all the foregoing genera, which bear two equal spines opposite to one another on the poles of the main axis; it differs from them in the multiplication of the cortical shell, and may be considered as the most highly developed form of this amphistylous series, which proceeds from Ellipsoxiphus to Lithatractus and Stylatractus.
Stratigraphic range: No information given.
Etymology: From the Greek cromyatractus = onion-spindle.
Subsequent descriptions: ?
Cromyatractus tetraphractus n. sp. Haeckel, 1887a, p. 335
(Pl. 15, fig. 2 (as Stylocromium tetraphractum))
|Description and dimensions :Proportion of the main axes of the four concentric shells about = 1: 3: 5: 7. Network of all four shells nearly of the same structure, subregular, with circular pores of equal size (in one and the same shell). The absolute size of the pores increases gradually from the innermost to the outermost shell. The bars between the pores are smaller and quite smooth. Surface of the outer most shell smooth. Polar spines cylindrical, with conical apex, of variable length, nearly as broad as the innermost shell.
Main axes of the four shells - (A) inner medullary shell 30µm, (B) outer medullary shell 80µm, (C) inner cortical shell 150µm, (D) outer cortical shell 200µm; equatorial axes of them - (A) 25, (B) 60, (C) 120, (D) 150µm; pores of (A) 4, (B) 7, (C) 10, (D) 13µm, bars 2 to 4µm; length of the polar spines 100 to 300µm (and more), breadth 15µm.
Remarks: [Haeckel here lists Cromyatractus tetraphractus under the subgeneric name Cromyatractium but does not include the subgeneric name in the species name.]
Repository: No information given.
Type locality: Antarctic [Indian] Ocean, "Challenger Exped." St.157 [53°55'S-108°35'E, 1950fms] diatom ooze with numerous Radiolaria.
Original stratigraphic range: Quaternary
Etymology: No information given
Subsequent descriptions: YES
Literature cited: - Campbell, A. S. (1954). Radiolaria. Treatise on Invertebrate Paleontology. R. C. Moore. Lawrence, Kansas, USA, Geological Society of America and University of Kansas Press. Part. D, Protista 3: 11-195.
Cromyatractus species Cromyatractus elegans Dogel