natural, history

Fig. I. Radula of Setaepoma mayri Clench.Setaepoma mayri, new species(Plate 17, fig. 5; text fig. I)Description. Shell depressed turbinate, thin and having three spiral rows ofbristle-like processes of periostracum on the outer whorl. Color a dark straw-yellow.Whorls 4 to 4 1 / 2 , strongly convex and tubular but only narrowly attached to thewhorl above. Spire depressed, the early whorls just appearing above the body whorl.Aperture nearly circular, holostomatous and exceedingly thin. No columella. Umbilicuswide and funnel-shaped, the early whorls to the nuclear whorls being visible.Suture very deep. Periostracum rather thick and forming rather long, thin, bristlelikeprocesses which are grouped to form three spiral crests. Fine thread-like andspiral ridges exist which are without the bristle-like processes. Nuclear whorls P/ 2osmooth and pinkish in color. Operculum calcareous with a periostracal base, depressedabove and with a papilliform nucleus on the lower inner surface. Outer surfacedeeply grooved with a spiral channel, the ridge between being flat and crossedby fine thread-like costae.Height Greater Diameter Lesser Diameter5.5 rom 8.2 mm 7.5 mm Paratype5.5 - 10.5 - 8.5 -7.5 - II 95.5 - 6.5 - 5.8 - HolotypeTypes. Holotype, Museum of Comparative Zoology, no. 36840, from Fulakora,Ysabel Island, Solomon Islands. W. M. MANN collector, 1918. Paratypes in the Museumof Comparative Zoology and the American Museum of Natural History fromalong the Wurulata River, Choiseul Island at 2500 feet elevation. ERNST MAYRcollector, Sept. 1929.Remarks. Setaepoma mayri is close in its relationships to S. hedigeri I. and B.Rensch from the Island of Bougainville. S. mayri is, however, more depressed, thespire hardly elevated above the body whorl and it has as well a much wider, funnelshapedumbilicus.168 •