GIBBULA. 203 



Var. BARBARA Monts. PI. 33, figs. 84. 



Spire elevated, conical, acuminate ; suture but feebly canaliculate ; 

 shell thinner and umbilicus narrower than in typical G. ardens. 



Gulf of Gabes. 



G. UMBILICARIS Linne. PL 32, figs. 63, 64, 65. 



Shell umbilicate, conical, cinereous, reddish, or purplish-brown, 

 obscurely clouded, dotted or flamed with white; spire conical, 

 acuminate; whorls about 7, slightly convex, spirally striate or 

 lirate, microscopically obliquely striate ; the line generally subobso- 

 lete on the last whorl ; periphery obtusely augulate ; aperture 

 rather small, oblique, rounded-quadrate, angld at the base, smooth 

 within ; columella arcuate above, straightened below. 



Alt, 12-16, diam. 14-20 mill. 



Mediterranean Sea. 



T. uirbilicaris LINN., Syst. Nat., xii, p. 1229 (1766). LAM., An. 

 s. Vert., vii, p. 28. FISCHER, Coq. Viv., p. 143, t. 45, f. 2. BUQ., 

 DAUTZ. ET DOLLFUS, Moll, du Rouss., p 376, t. 45, f. 1-8. T.fits- 

 catus GMEL., Syst. Nat., xiii, p. 3576. DESHAYES, Exped. Moree, p. 

 142. Gibbnla mediterranea R'ISSO, Hist. Nat. TEur. Merid., iv, p. 

 136. G. desserea Risso, toe. cit., p. 136. T. roissyi BLAINVILLE, 

 Fanne franc., p. 282, t, lOa, f. 9. T. zonatus JEFFREYS, Piedin. 

 Coast, p. 28. T. umbilicaris var. latior et patula (MoNTEROSATo) 

 BUG., DAUTZ. et Dollfus, Moll. Mar. du Eouss., p. 378, t. 45, 

 f. 6, 7, 8. 



A species very closely related to G. ardens v. Salis. It differs in 

 the smoother, more angulated body-whorl ; the less canaliculate 

 sutures ; rounder mouth ; deeper umbilicus, which, although as broad 

 (or nearly so) as in G. ardens, is much less funnel-shaped, but nearly 

 of the same width to a considerable depth ; the whorl is also more 

 angulated around the umbilicus than in the other species, and the 

 columella is not dentate, 



The coloration is extremely variable, as in nearly all the Mediter- 

 ranean Trochids. In fact nearly every species of the smaller 

 Trochidse of this province exhibits the same patterns and modifica- 

 tions in coloration, commencing with (1) a series of white flames 

 beneath the sutures, which (2) are continued as longitudinal, oblique, 

 or undulating stripes to the base, or (3) are broken into maculations 

 or articulations over the whole surface, or (4) the entire surface is 

 either creamy wlfite or uniform dark. 



