Strophiops periculosum Clench, 1934

Original Description

 "Cerion (Strophiops) periculosum, sp. novo Plate 2, figure B.

Description. - Shell cylindric, ribbed, heavy and rather stout. The umbilical chink consisting of a short and rather shallow rimation. Color flat white to faintly mottled between the ribs. Whorls 9¾, first 1½ to 2 glasslike and opaque, very faintly ribbed, remaining whorls porcelaneous, and rather coarsely ribbed, the ribs numbering 23-30 on the body whorl. First 6 whorls forming a short cone, remain­ing whorls about equal in diameter. Spire produced at an angle of 59°. Aperture rounded to rounded ovate rather flat at the parietal margin and colored a light brownish purple, well below the lip. Parietal tooth centered and fairly well developed. Axilla or columellar lamella much smaller, occasionally absent, and usually starting well within the aperture. It generally follows back about ¾ of a whorl.  Lip well developed and somewhat thickened, slightly reflexed and well ridged over the parietal region. Sculpture of strong axial ribs and fine irregular growth lines. Occasional specimens possess one or more incised hairlike spiral lines usually only indicated on the body whorl and generally located at or a little below the periphery of the whorl.

 

Measurements.

 Length

Width

Aperture  length

Aperture width

  25.6

 11.2

  6.5

6.0  mm.

Holotype

  26.6

 11.3

  7.5

6.5

Paratype

  27.0

 11.0

  7.5

6.0

      "

  26.5

 11.0

  7.5

5.8

      "

  26.0

 11.2

  7.0

5.5

      "

  25.0

 12.5

  7.2

6.0

      "

  23.6

 11.5

  7.0

6.0

      "

  23.2

 11.5

  7.5

6.0

      "

  26.0

 11.0

  7.0

5.8

      "

  21.5

 10.0

  6.8

6.0

      "   

Types. -Holotype M.C.Z. no. 103,019 and paratypes no. 103,020, South Cay, Mira Por Vos group, Bahamas. Mr. and Mrs. J. C. Green­way, collectors, March 6, 1934.

This species is very close to C. blandi P. and V. (1896, p. 334) de­scribed from Turk's Island. All measurements are approximately equal for both species (Pilsbry's measurements of the aperture are between the outer edges of the lip, the measurements given for periculosum are between the inner faces of the aperture, however, these measurements are about equal when measured in the same way). C. periculosum differs from C. blandi by possessing more ribs (23-30 as opposed to 19-22) and having a somewhat shorter coneshaped spire.  It is of particular interest that another member of the glans group is found in the lower chain of islands, a group of species which is extraordinarily rich in the Andros-New Providence-Exuma Island por­tion of the Bahamas.  No species of this group has as yet been found on the islands of the Crooked Island Bank which is not far distant from the Mira Por Vos group." (Clench, 1934:215-216)

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