"Cerion (Multostrophia) lewisi, new species

Plate 43, fig. 5

Description. Shell cylindrical, rather elongate, rather light in structure, smooth to finely ribbed and rimately perforate. Color a shining reddish brown and irregularly marbled with white. Whorls 10½ to 11, slightly convex, the first 7 whorls forming the tapering apex. Suture well defined. Aperture ovate to subcircular. Lip slightly thickened, narrowly reflected and recurved. Parietal ridge moderately to well developed. Parietal tooth centered and extending backwards for t whorl. Columella tooth formed well within the aperture and extend­ing backward for ½ whorl. Umbilicus small. Sculpture consist­ing of fine, irregular, axial ribs.

length               width

32mm.             12.4 mm.          Holotype

32                    12.5                 Paratype

30.5                 11                    Paratype

29.5                 11                    Paratype

Types. The holotype is in the United States National Mu­seum, no. 610286, from Pine Cay, Caicos Islands, Bahama Is­lands. Paratypes from the same locality are in the Museum of Comparative Zoology, no. 221564, Paul Bartsch collector, July 24,1930.

Remarks. C. lewisi is not closely related to any other species of Cerion in the Turks and Caicos Islands.  It appears to be nearest to C. lepidum Clench and Aguayo of Punta de Mulas, Banes, Cuba, the same species which may be ancestral to the C. rubicundum Menke complex on Great Inagua. It is to be noted that this species is limited to the northwestern cays of the Caicos Islands.

     It is quite possible that all species in the subgenus Multotrophia are derivatives of C. lepidum from Cuba. In general, the species in this subgenus are rather light in structure, most are finely ribbed or smooth, and in the Bahamas occur on the western sides of the large islands or the western cays of the small island groups.