CADULUS-GADILA. 191 



. ACUS Dall. PL 36, fig. 27. 



Shell small, very slender, slightly curved, variegated with trans- 

 lucent and opaque white rings and encircling bands, which become 

 broader toward the anterior extreme ; aperture circular, slightly ob- 

 lique, the shell behind it rapidly increasing to its point of maximum 

 diameter, from which it very gradually tapers toward the almost 

 acute posterior extremity. Surface smooth, with extremely fine 

 circular grooves or lines, which under a strong magnifier are visi- 

 ble over most of the posterior third ,of the shell, with their inter- 

 spaces, recalling the rings of Ccecum trachea on a much more minute 

 scale ; the rings of opaque color sometimes coincide with the sculp- 

 ture, but not constantly. Length of shell 8*0, diameter of aperture 

 0'5, greatest diam. 0'75, posterior diam. 0*12 mill. (Dall}. 



Samana Bay, S. Domingo, in 30 fms. (Capt. Couthouy, U. S. N.). 



Cadulus acus DALL, Bull. M. C. Z., xviii, Blake Rep., p. 432, pi. 

 27, f. 11 (1889) ; Bull. U. S. Nat. Mus., No. 37, p. 78, pi. 27, f. 11. 



Very closely allied to C. dentalinus Guppy of the Jamaican Oli- 

 gocene or Miocene, and possibly also to C. dominguensis d'Orb. 



. DOMINGUENSIS (Orbigny). PL 36, fig. 26. 



Shell lengthened, narrow, arcuate, smooth and shining; apex 

 acuminate. Length 7 mill. (Orb.). 



San Domingo t Martinique and Cuba, on the sand (Orb.). 



Dentalium dominguense D'ORB., (" 1846 "), Hist, etc., d'lle de 

 uba (de la Sagra), Moll., ii, p. 201 (1853) ; Atlas, pi. 25, f. 7, 8, 9. 



This little species is easily recognized by the contraction of the 

 aperture, which is oblique and oval. (Orb.). 



It is known only by d'Orbigny's description and figures. Type 

 was deposited in British Museum (Catal., p. 34). 



O. PANAMENSIS Sharp & Pilsbry, n. sp. or var. PL 36, figs. 23, 24 



25. 



Shell very slender, aeicular, quite arcuate, the bend mainly poster- 

 ior ; encircled quite near the aperture by a convexity or swollen band, 

 from which it contracts rapidly to the aperture, and posteriorly 

 tapers gradually to the small apex ; circular in section. Bluish- 

 white, a little translucent, the anterior swelling opaque white. Sur- 

 face closely and finely sculptured with encircling wrinkles or riblets 

 from the apex nearly to the middle, the remainder smooth except 

 for light growth-lines, shining. Aperture circular, somewhat ob- 

 lique ; apical orifice circular with unslit edges. 



