1913.] NATURAL SCIENCES OF PHILADELPHIA. 11 



beginning to appear generally on the second whorl and sometimes 

 continuing to the lip, but dying away towards the periphery, or, 

 if they cross it, not producing a thickening of the hrae at this point. 

 Whorls six or somewhat over (6.3) and rarely less than 5.7. The 

 revolving strise become fainter and are almost obsolete in the 

 umbilicus. The number of these revolving strise varies through 

 the appearance of interstitial lirse between those already existing, 

 which eventually develop to the same size as the others. There 

 are generally about 45 lirse on the last whorl, of which 18 or 20 

 are above the periphery, they are close and even and are not thick- 

 ened where the oblique wrinkles cross them. The size varies with 

 the locality, ranging from diam. = 10 mm. by alt. = 7.7 mm. 

 (Pfeiffer) to diam. = 5.6 mm. by alt. =4.3 in the smallest specimen 

 taken in the vicinity of Mandeville. 



This smallest specimen, which came from the Lower Santa Cruz 

 Road about three miles from Mandeville is simply a diminutive 

 reproduction of the largest which was found at Somerset, with 

 somewhat fewer whorls but \vith none of the peripheral granulation 

 observed on some of the Montego Bay specimens (Plate I, figs. 

 22-26). These latter, which, as stated above, were collected on the 

 Orange Hill and the Rose Mount estates, differ from the typical 

 L. aureola above described in certain specimens. In about one-half 

 of the Orange Hill specimens and about one-third of the Rose Mount 

 specimens an additional sculptural feature is present. The pe- 

 riphery of the last whorl is raised into a series of points or tubercles, 

 by the thickening of one or more of the peripheral lirse where they 

 are crossed by the transverse oblique wrinkles which are present in- 

 all specimens of this species examined. This structure is exactly 

 comparable to the development of the granulate sculpture on L. 

 granulosa which has been described. A careful examination of the 

 young of typical L. aureola from some fifteen localities shows that 

 while the oblique transverse wrinkles are common to all of them, 

 these do not produce any granulation on the periphery, so that this 

 is not, as in the case of the dwarfed races of L. granulosa, a "rever- 

 sion" or the effect of the individual's maturing at what is normally 

 a young stage, but actually a new sculptural character which has 

 developed in these Montego Bay forms. It only appears distinctly 

 on the last whorl, the tubercles becoming stronger after the periphery 

 emerges from the suture, but it may be present on the preceding 

 whorl also, as the corrugations or wrinkles are found well developed 

 on both the last and next to the last whorls. When well developed, 



