46 DENTALIUM-ANTALIS. 



In some specimens of D. pretiosum before us the apical notch is 

 excentric, and in one it is directly lateral, as in D. sericatum, although 

 having the form usual in pretiosum and entalis. We have observed 

 similar inconstancy in the position of the slit in some other species. 



D. AGILE M. Sars. PL 8, figs. 36. 



Shell very long and narrow, somewhat attenuated toward the apex ; 

 very slightly curved, almost straight, not very solid. White, little 

 shining, generally smooth, rarely lightly striolate toward the apex. 

 Apical fissure rather deep. Length 57 mill. (G. 0. Sars). 



Lofoten Is., etc., Norway (Sars) ; Baxj of Biscay (Travailleur) ; 

 Mediterranean and Adriatic Seas (Spratt, Stossich) ; Canaries, Azores 

 and Ascension I., 420-620 fms. (Challenger, Josephine Exped.) ; 

 Between Halifax and La Have Bank (U. S. F. C.) ; Off Morro Light, 

 Havana, Cuba, 400 fms. (Blake). 



D. agile M. Sars, Remarkable Forms of Anim. Life, etc., p. 34, 

 pi. 3, f. 4, 5 (l^l2).—AntaUs agilis G. O. Sars, Moll. Reg. Arct. 

 Norv., p. 102, pi. 20, f. 9 (1878).— Monts., Nomencl. Gen e Spec. 

 ■Conch. Medit., p. 32.— Z). agile Dall, Bull. M. C. Z., ix, p. 37 

 (1881); ibid., xviii, Blake Rep., p. 418 (1889); Trans. Wagner 

 Inst., iii, p. 44 (1892). — Sturany, Ber. Commis. Erforsch. ost. Mit- 

 telm, p. 29.— Jeffreys, P. Z. S., 1882, p. 658 ; Ann. Mag. N. H. 

 (5), X, p. 30 (1882) ; Nature i, p. 166, no description (1869).— Z>. 

 entalis var. agile Sars, Watson, Challenger Rep., p. 6 (1885). — 

 Smith, P. Z. S., 1890, p. S21.—D. incertum Phil., Enuni. ]\[oll. 

 Sicil., ii, p. 207, (1844), not D. incertum Desh. — D. vagina Jeffreys, 

 see below. — D. fusticulus Brugnone, Misc. Malac, ii, p. 21, f. 31. 



" I now find that, compared with D. striolatum or abyssorum, the 

 present species is more slender and not so strongly ribbed, and that 

 the curve is more gradual and not abrupt towards the point or 

 base. Perfect specimens of both species have a short terminal pipe 

 within the slit and occasionally issuing from a truncated and thick- 

 ened base, as in D. dentalis and D. tarentinum. Philippi was the 

 first to describe D. agile from the Italian Tertiaries as D. incertum 

 of Deshayes; but it is not the last named species. It was dredged 

 in the 'Porcupine' and 'Travailleur' expeditions off the Lusitanian 

 coasts." (Jeffreys). 



D. vagina Jeffreys. (PI. 9, fig. 52). Narrowly cylindrical, 

 rather solid, glossy, smooth. Its peculiarity consists in the posterior 

 termination forming a second and narrower cylinder, which issues 



