52 DENTALIUM-ANTALIS. 



Sacco recognizes ' yaneties' pseiidaprina, inutabilis, inccquicostaia 

 decemcostata, undecemcostafa, duodecemcostata and tredecemcostata in 

 the Italian Pliocene. They are probably mere forms, and may be- 

 long to the closely allied D. incequicostatum Dautz. 



D. iN^QUicosTATUM Dautzenberg. PL 9, figs. 49, 50, 51. 



Shell moderately or slightly arcuate, either decidedly or slightly 

 tapering, very solid, nearly lusterless. Whitish, with numerous ill- 

 defined orange-red or roseate zones, and sufliised with that color to- 

 ward the apex. Sculpture of 9-12 strong primary ribs toward the 

 apex, narrower than their intervals, which are smooth except for 

 very faint, close longitudinal striation, and rather conspicuous 

 growth -strise; smaller secondary ribs, alternating with the others, 

 soon appear, and toward the aperture, where the sculpture becomes 

 weaker, some tertiary cords ; so the ribs are rather irregularly alter- 

 nating in size ; adults showing some irregular, shallow or deep con- 

 strictions around the tube, caused by interrupted growth or break- 

 age. Aperture subcircular, slightly polygonal, somewhat oblique. 

 Apex wide and truncate in adults, with a small, short central tube. 

 No slit or notch. 



Length 50, diam. of aperture 4*5, of apex 2 mill. (Specimen). 



Length 35, diam. of aperture 5 mill. (B. D. & D.). 



Mediterranean, from Greece and Sicily to southern France, Algeria 

 and Tunis ; laminarian zone. 



D. dentalis Lam., An. s. Vert., v, p. 344. — Risso, Hist. Nat. Eur. 

 M^rid., iv, p. 398.— Desh., Mem. Soc. H. N. Paris, ii, p. 353, pi. 16, 

 f. 9, 10.— Philippi, Enum. Moll. Sicil., i, p. 243 ; ii, p. 206.— Jef- 

 freys, Ann. Mag. N. H., 1870, p. 10. — Monterosato, Not. int. 

 alle Conch. Medit., p. 28 ; Conch, delle Rada di Civitavecchia, p. 8. 

 Not D. dentalis Linne. 



D. fasciatum Lam., 1. c, p. 343. Not D. fasciatum Gmel. 



B. novemcostatum Lam., Payr., Moll, de Corse, p. 19. — Jef- 

 freys, Moll. Piedm. Coast, p. 26. — Weinkauff, Conch, des Mit- 

 telm., ii. p. 420. — Monterosato, Nom. Gen. e Spec, p. 31. Not £>. 

 novemcostatum Lamarck. 



? D. striatulum De Blainv., Diet. Sci. Nat., xiii, p. 70 (1819). 



D. pseudo-antalis Scacchi, Catal. Conch. Reg. Nap., p. 17 (1836). 

 Not D. pseudo-antalis Lamarck. 



D. alternans BuQ., Dautz. & Dollf., Moll. Mar. du Roussilon, 

 i, p. 561, pi. 66, f. 7, 8, 9. Not D. alternans Chenu. 



