. Bulletin - United States National Museum. Science. CENTRAL PKOVINCE SPECIES. 171 figure) very low, wide, with one inner, long, blunt cutting point, and one outer, small, blunt. Tbe low, wide marginal teeth of this species are peculiar. SPURIOUS SPECIES OF MICROPHYSA. Microphysa mlnuscula of Von Martens (Alb., eel. 2) is a Zonites (q. v), POLYGYRErLA, Bland. Animal heliciform; mantle subceutral; other characters as in Pa- tula. Shell widely umbilicated, discoidal, ribbed above, smoother below; whorls 7-8, gradually increasing, the last fio. igi. deflected above, furnished within with two rows
. Bulletin - United States National Museum. Science. CENTRAL PKOVINCE SPECIES. 171 figure) very low, wide, with one inner, long, blunt cutting point, and one outer, small, blunt. Tbe low, wide marginal teeth of this species are peculiar. SPURIOUS SPECIES OF MICROPHYSA. Microphysa mlnuscula of Von Martens (Alb., eel. 2) is a Zonites (q. v), POLYGYRErLA, Bland. Animal heliciform; mantle subceutral; other characters as in Pa- tula. Shell widely umbilicated, discoidal, ribbed above, smoother below; whorls 7-8, gradually increasing, the last fio. igi. deflected above, furnished within with two rows of three teeth ; base flattened ; um- bilicus of equal size to the apex ; aperture subvertical, oblique, lunate-oval 5 peri- jn^ stome white, simple, much thickened within, margins joined by a white, jiliciform, elevated, triangular tooth. Central Province ; a single species known. Jaw of the onlj' known species, P. poJygyrella, very low, wide, very slightly arcuate, ends very gradually attenuated ; cutting margin with- out median projection; anterior surface with numerous (even 20) broad, slightly separated ribs, denticulatiug either margin. Lingual membrane (Terr. Moll., V, Plate VII, Fig. A) long and nar- row. Teeth 27-1-27, with 5 perfect laterals. Centrals sub(iuadrate, the lower lateral angles but little exi)anded, the upper margin broadly reflected ; reflection large, wide, with distinct but small, rounded side cusps, bearing short conical cutting points, and a very stout median cusp, reaching the lower margin of the base of attachment, beyond which projects the short, stout, conical cutting point. Laterals like the centrals, but asymmetrical by the suppression of the inner, lower angle of the base of attachment and the inner side cusp and cutting point. First marginals a simple modification of the laterals by the lesser development of the cutting point {h). Outer marginals (c) low, wide, the reflection equaling the base of attachment and bearing one inn
Size: 2646px × 944px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
