Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 71. (Budapest 1979)

Szabó, J.: Lower and Middle Jurassic Gastropods from the Bakony Mountains (Hungary). Part I.: Euomphalidae (Archaeogastropoda)

Fig. 5. Measurement ratios of the here described Discohelix and Pentagonodiscus species. Each specimens with measurable dimensions correspond to one point. These are derived from the corresponding H, D and S values and the HjD and HjS ratios. Dimensions measured at strongly tapering peristome give markedly deviate value (see letter P). 1 = D. inornata, 2 = D. orbis, 3-D. excavata, 4 = D. miocarinata, 5 — D. acarinata, 6= P. reussii, 1 = P. initiopentagonatus, crosses indicate P. angustus and arrows indicate ?Z>. cotswoidiae Remarks — Because of the imperfect preservation, the specific identification of these fragments is merely presumable. The D. orbis figures of M. GEMMELJLARO (1912) show only more widely spaced tubercules and ridges than those on the specimens from the Bakony Mountains. Distribution — Alps, Hierlatz limestone; Eastern Sicily, "Terebratula aspasia zone"; Bakony Mountains: Sümeg, ? Upper Sinemurian. Discohelix excavata (REUSS, 1852) (Plate I: fig. 5; Fig. 6 d) 1852: Euompltalus excavatus REUSS-REUSS, p. 115., pi. 14., fig. 2. 1861 : Discohelix excavata REUSS-STOLICZKA, p. 184., pi. 3., fig. 12. 1912: Discohelix excavata REUSS-TONI, p. 39., pi. 2., fig. 5. 1912: Discohelix excavata REUSS-M. GEMMELLARO, p. 216., pi. 9., fig. 13. 1920: Discohelix excavata REUSS-CHAVANNE, p. 54., pi. 4., fig. 5. Measurements: D H S H/D H/S A U Plate I: fig. 5 19.7 9.3 6.6 0.47 1.41 206° 122° Material — Thirteen specimens, mainly moulds with test fragments. Unfortunately, the most characteristically sculptured last whorls are damaged in the majority of the specimens, however, these fragments can be identified with ce tain ty. Shape — Dextral, discoidal, biconcave forms with deeper umbilical side. The surface of the whorls are nearly flat on the spiral and umbilical, and strongly convex on the outer side. The keels are distinct and carinated throughout after the first whorl. The peristome is simple. Sculpture — The ornamentation appears on the third or fourth whorl, and it consists of tiny, roof-tile-like, posteriorly dipping transverse bars. These start from the sutures and strengthen into small nodes on the carinae, then die out rapidly outward. These bars are divided by extremely fine growth-lines. The bars appear repeatedly up to the last whorl, where these are substituted by strong growth-lines. These strong growth-lines appear firstly in bundles, than the bundles strengthen