54 DENTALIUM-ANTALIS. 



Foresti, in Bull. Soc. Mai. Ital., xix, p. 249-252, admits these 

 varieties from the Pliocene : (1) alternans B. D. D., (2) ohsoleta 

 Dod. (=D. obsoletum Doderlein, Genu. Geol. giacim. terr. Mioc. 

 sup. Ital. Centr., p. 15, 1862 ;=i). dentalis var. siiblcevis Cocconiy 

 Enura. sistem. Moll. Mioc. e Plioc. Parma e Piacenza, p. 240, 1873), 

 and (3) cequicostata Foresti, 1895. Whether these are really refer- 

 able to dentalis or not is uncertain ; the recent forms of this group 

 are certainly closely allied though probably specifically distinct, but 

 some convergence is to be expected in the tertiaries. 



D. PANORMUM Chenu. PI. 9, figs. 38, 39. 



Shell slender and elongated, moderately curved, solid. Flesh- 

 tinted, or opaque white and tinted posteriorly, where it is also often 

 encrusted with a black deposit. Sculpture of about a dozen unequal 

 narrow riblets at the apex, increasing in number but losing in prom- 

 inence as the tube enlarges; growth striae scarcely noticeable, but 

 there is often a deep jagged encircling constriction where a former 

 fractured peristome has been repaired. Aperture circular, hardly 

 oblique. Anal orifice small, circular or ovate, with thick walls. 



Length 53, diam. of aperture 4, of apex 1 mill. 



Length 70, diam. of aperture 4, of apex r5 mill. 



Mediterranean and Adriatic Seas ; Bay of Biscay, 30-195 fms. 



D.panormum Chenu, 111. Conch., i, p. 6, pi. 6, f 13 (1842-1847). 

 — D. panormitanum Jeffreys, P. Z. S., 1882, p. 657. — Stur- 

 ANY, Denkschr. Kais. Akad. Wissensch. Wien., Ixiii, Berichte der 

 Coramis. fiir Erforsch Ostl. Mittelm., p. 29. — D. lesso7ii Sowb., Thes. 

 Conch., iii, p. 100, pi. 224, f. 17, 18.—? And Clessin, Conchyl. Cab. 

 p. 7. Not of Deshayes. — ? D. arguticosta Brugnone. 



D. pseudoantalis O. G. Costa, Fauna Reg. Nap., Dent., p. 17, 

 pi. 1, f. 2, 8 (1850). 



Independently of the much greater length, the ribs are finer and 

 far more numerous and regular, (than in dentalis), and they are ex- 

 tremely slight or become mere stride on the anterior part or in front. 

 The shell is also more tapering and proportionally narrower. It 

 attains the length of 3 or 4 inches. Some specimens have the same 

 pipe at the posterior extremity as in D. dentalis. (Jeffr.). 



D. panormum, like the very closely allied dentalis and incequicosta- 

 tum, repairs a broken peristouie very clumsily, leaving a gaping record 

 of the injury, deeper than in most species of the genus ; such breaks 



