CYMBULARIA ALATA. 63 



Kentucky, rather than any European species. The generic reference of this Welsh 

 form is doubtful, but probably it belongs to Bucaniopsis. 



Genus CYMBULARIA, Koken. 



Generic Characters. — Shell involute, more or less laterally compressed; 

 umbilicus closed on one or both sides. Outer whorl with distal portion angulated 

 and carinated, but rest of whorl rounded. Aperture with long narrow dorsal slit 

 and lateral lips infolded. Otherwise like Bellerophon. 



This genus was established by Koken 1 in 189G with Bellerophon cultrijugatus, 

 Roemer, 2 from a boulder of Orthoceras Limestone, as its- type. This species 

 has apparently a closed umbilicus, though Koken says the genus has an open 

 one, but he included B. globulus, Lindstr., which has it closed, and Perner has 

 pointed out that the umbilicus may be closed only on one side by a callosit}^. 

 The outer half of the last whorl is said to be characterised by a prominent 

 keel and to be compressed, with a narrow dorsal slit reaching some distance 

 back ; but the rest of the dorsum is rounded. There is an occasional want 

 of symmetry in the shell to which Perner calls attention. But Koken makes 

 no mention of the infolding of the lateral edges of the mouth as shown in 

 his figure of G. galeata, Koken, 3 the first member of his genus which he 

 illustrates. This feature is also well seen in the so-called Bellerophon (Oxydiscus ?) 

 incola, Barrande, as figured by Perner. 4 It is a character of some importance 

 and is found also in the genus Euphemus as understood by Waagen. 5 The 

 expanded mouth of Bellerophon with frecpiently outwardly bent margins is 

 strikingly different. Neither in Zittel-Eastman's Textbook (2nd ed., 1913) nor in 

 Bassler's Index (Bull. 92, U.S. Nat. Mus., 1915) is the genus mentioned. The 

 angulation or carination of the distal part of the last whorl near the mouth is 

 found also in Perner's Prosoptychus, a section of Bellerophon-, but the umbilicus 

 is always closed, and the lips are reflected in that section. 



1. Cymbularia alata (Portlock). Plate X, figs. 10, 11. 



1843. Bellerophon alatus, Portlock, Greol. Rep. Londoud., p. 471, pi. xxxiii, fig. 9. 



Specific Characters. — Shell involute, lenticular, thickest at umbilicus ; whorls 

 triangular, as high or rather higher than wide ; outer whorl completely enveloping 

 inner whorls, with acutely angulated dorsum; sides slightly convex or flattened 



i Koken, ' Leitfossilieu ' (1896), p. 392. 



2 Roemer, 'Leth. G-eogn.,' vol. i, Palaeoz. (1876), Atlas, pi. v, figs. 10 a, b. 



3 Koken, ' Gastrop. Bait. Untersilur.,' Bull. Acad. Imp. Sci. St Petersb., ser. v, vol. vii, no. 2, 

 1897, p. 115, fig. 2. 



4 Perner, op. cit., p. 160, pi. lxxxvii, figs. 9 — 11. 



■' Waagen, 'Salt Range Fossils ' ('Palseont. Ind.,' ser. xiii), vol. i (1887), p. 163, pi. xiv, figs. 9a — d. 



