GLYPHIOCERAS (SPHENOCERAS) CRENISTRIA. 150 



1903. GoNiATiTES CKENisTKiA. Jas. Pcrriii Smith. " The Carbouiferous Ain- 



monoids of America," U.S. Geol. 

 Surv., Mon. xlii (pp. 1—211, 2<} 

 plates). Author's Abstract iu Geolo- 

 gisches Centralblatt, Bd. iii, No. 13, 

 p. 680. 



Deacnptlon. — "Shell subglobose; greatest thickness in the adult at a short 

 distance from the margin of the uml^iliciis, in immature specimens at the margin of 

 the umbilicus, about three-fifths of the diameter of the shell ; height of outer whorl 

 a little more than one-half of the diameter of the shell. Whorls six or seven ; 

 inclusion almost complete ; umbilicus small, open, about one-tenth of the diameter 

 of the shell in width. Whorl semi-elliptical in section, rather wider than high ; 

 indented to from one-half (in the young) to one-third (in the adult) of its height by 

 the preceding whorl ; periphery l)roadly convex ; sides not very convex, rather 

 flattened, the portion around the uml)ilicus jn'ominent in the adolescent stage, 

 slightly depressed in the adult ; inner area imperfectly defined, in the cast almost 

 at right angles to the plane of symmetry. Body-chamber occupying a complete 

 whorl, aperture not seen. Chambers shallow, nineteen or twenty to a whorl. [Suture- 

 line as in PL XLII, fig. 5.] Test thin, with fine, crenulated, feebly reticulated, 

 curved, transverse strias, which form a broad, forwardly concave sinus on the 

 periphery; liecoming almost smooth in tlie adult. Shell attaining a diameter of 

 6() mm." (' Cat. Foss. Ceph. British Museum,' loc. cit.) 



Affinities. — The distinguishing feature of this species is the crenulation of the 

 transverse striae covering the test. In form it resembles Gli/phiocerds titriatui<, 

 J. Sow., with which de Koninck has indeed united it, but its suture-line is quite 

 distinct from the latter, and Avould in itself be a sufficient ground for separating the 

 two species ; the umbilicus is also smaller than that of G. str'uiUiis. 



Remarks. — A well-preserved septate specimen, 38 mm. in diameter, with 

 fragments of the test, is contained in the British Museum (Morris Collection, No. 

 50,183); this specimen is the one figured (PI. XLII, fig. 5). 



Phillips has recorded this species from Queen's County and the county of 

 Fermanagh, as well as from Bolland, and the Isle of Man. 



Localities. — Queen's County; county of Fermanagh. (The British i\luseuni 

 specimen cited above is labelled " Ireland " only.) 



