1 I THE BRITISH CONULAREE. 



SYSTEMATIC ACCOUNT OF BRITISH SPECIES. 



Family Conulaiuid2e. 



Genus CONULARIA, Sowerby 1818 [ex Miller MS.] 



Diagnosis. — Shell a four-sided, elongated pyramid — nearly always straight. 

 Cross-section a square, rhomb, rectangle or rhomboid-, or the corresponding 

 figures where the straight lines are replaced by curves. Faces of the pyramid flat, 

 convex or concave ; all equal or equal only in opposite pairs. Angles of the 

 pyramid marked by straight grooves. Aperture partially closed by infolding lobes, 

 apex sharply tapering ; apical part of shell divided up into a few compartments by 

 thin convex, probably imperforate septa. Shell smooth, or ornamented with a 

 series of ridges, sometimes longitudinal, more often transverse. Shell very thin, 

 formed of chitin, more or less impregnated with lime. 



Section I.— L /EVES. 



Shell without transverse ornamentation, except growth-lines. 



(a) Shell large, very thin; marginal and facial grooves well marked; growth- 

 lines irregular and often imperceptible. 



(i) Shell smooth, except for a single ridge down the centre of the face. 



G. llanvirnensis, Hicks. 

 (ii) Shell with a well-marked central facial groove, flanked by two very 

 faint secondary grooves ; tapering of shell very gradual. 



G. curium, Salter. 



(iii) Marginal and central facial grooves bounded by prominent edges ; 



tapering of shell more rapid. 0. homfrayi, Salter. 



(b) Shell small ; growth-lines strongly marked. 



(i) Marginal and central facial grooves strongly marked and usually with 

 prominent edges. Growth-lines horizontal. G. linnarssoni, Holm. 

 (ii) Facial grooves absent; growth-lines gently arched across the face. 



G. laevigata, Salter. 



Conularia llanvirnensis, Hicks. 



1875. Conularia llanvirnensis, H. Hicks, Quart. Journ. Geol. Soc, vol. xxxi, p. 189, pi. xi, figs. 5, 6. 



Diagnosis. — Shell large, very thin, tapering uniformly ; cross-section unknown. 

 Faces flat, apical angle of face 5° — 6°. Marginal groove unknown; strong central 



