CUBAN ANNULARiroAE TORRE AND BARTSCH 353 



the summit and the suture, and 9 on the last. The spiral threads 

 render the stronger axial riblets slightly nodulose and the finer wavy. 

 Suture slightly channeled. Periphery of the last whorl well rounded. 

 Base short, strongly rounded, marked by the continuation of the axial 

 ribs and by 10 spiral threads, which are of almost equal strength. 

 The umbilicus is broadly open and marked by the feeble continua- 

 tion of the axial ribs and by 8 spiral threads, which become consecu- 

 tively stronger and a little more distantly spaced from within toward 

 the outside, the outermost being the strongest. Aperture almost 

 circular; peristome double, the inner and outer being coextensive on 

 the outer and basal lip and differentiated only by an impressed line on 

 the inner lip and at the posterior angle. At the posterior angle the 

 outer peristome forms an auricle. Operculum typically annularid. 



The type, U.S.N. M. No. 535661, was collected by Dr. Ramsden at 

 Ocujal, Vega Grande, Oriente Province. It has 4.5 whorls and 

 measures: Length, 8.3 mm.; greater diameter, 12.7 mm.; lesser diam- 

 eter, 9.5 mm. 



ANNULABIA (ANNULAREX) MACKINLAYI ([Gundloch] Pfeiffer) 



Plate 44, Figures 4-6 



1859. Cyclostoma mackinlayi [Gundlach] Pfeiffer, Malakozool. Blatter, vol. 



6, pp. 73-74. 

 1861. Cistula mackinlayi Bland, Ann. Lyceum Nat. Hist. New York, vol. 7, p. 27. 

 1920. Tudora (Tudorellata) mackinlayi Henderson and Bartsch, Proc. U. S. 



Nat. Mus., vol. 58, p. 75. 



Shell broadly turbinate, straw colored. Nuclear whorls and the 

 peristome a little paler; interior of the aperture pale orange. Nuclear 

 kvhorls 2, well rounded, microscopically granulose, except the last 

 portion of the last turn, which shows the beguming of the postnuclear 

 ixial sculpture. Postnuclear whorls inflated, very broad, marked by 

 'etractively slanting, sublamellar axial riblets, between which finer 

 ixial threads are present; the coarser riblets are slightly expanded at 

 ^hcir summit. Of the coarser riblets, 54 occur on the third, and 74 are 

 >n the last whorl. The finer riblets between the stronger lamellar 

 •ibs vary from 2 to 5 in number; in addition to the axial sculpture, the 

 :)ostnuclcar whorls are marked by spiral threads, of which 6 occur on 

 :,he third and 13 on the last whorl between summit and suture. The 

 unctions of the spiral threads and the sublamellar axial riblets form 

 eeble nodules, while the intercalated riblets are merely rendered some- 

 vhat wavy by the spiral threads. Suture channeled. Periphery well 

 'ounded. Base short, strongly rounded very openly umbilicated, 

 narked by the continuation of the axial sculpture and 1 1 spiral threads, 

 lie latter a trifle weaker than those on the spire, but they also affect 

 he axial riblets in the same manner as they do on the spire. The 



