4 THE NAUTILUS. 



bulging about the middle, and thence tapering towards the bottom ; 

 whorls slightly convex, obtusely angulated at the periphery, sculp- 

 tured with strong, thick lamella-like costulae crossing the whorls 

 obliquely, generally curvilinear, irregular in some places and wavy 

 here and there, extending to the very shoulder of the whorls, the last 

 whorl with a prominent carina which extends to the back of the base 

 of the aperture close to the peristome ; suture well incised ; aperture 

 inclining to the right, the plane very oblique, peristome thick, nearly 

 white, smooth and shining, reflected all around, with a very large, 

 strong, elevated knob close over the spot where the columella! - lip 

 should merge into the columella, and apparently arched over the 

 space of the entering rima beneath. Total length, 11 mm.; greatest 

 breadth at middle of spire, 3 mm.; next above the aperture, 2 mm.; 

 at the truncation, "2 mm. 



This shell was collected by me among tine earth and vegetable 

 debris taken from the roadsides near to Brown's Town, in the parish 

 of Saint Ann. Unfortunately, as its presence was only revealed to 

 me when searching this debris some time afterwards at home, no 

 note was kept of the exact habitat and station. It is as yet unique 

 in my collection. It is unlike any species of Anoma with which I 

 am acquainted, and its peculiarities would seem to warrant the 

 creation of a new subgenus, or at least of a special section to receive 

 it. The reasons for this appear to me to be as cogent as were those 

 which led to the creation of the subgenus Chittya for Geomelania 

 sinuosa. 



Cylindrella {TTiaumasia) instabilis Vendryes. PI. I, figs. 9, 10. 



Shell ovate-cylindrical, solid, rimate ; color dark-sanguineous, 

 not unlike that of some specimens of Cyl. sanguined, but the sur- 

 face of instabilis exhibits in most specimens semi-hydrophanous, more 

 or less wide, transverse patches sparsely and irregularly occurring, 

 and apparently produced by some indistinct lesions of the very thin 

 epidermis; spire describing a well drawn-out ovate outline; apex 

 broadly truncate with the loss of 6 to 7 of the earlier volutions, 

 whorls remaining 7 to 8, almost entirely plane in some examples, or 

 moderately convex in others , subarcuately, obliquely and closely 

 costulate stria- ; the last whorl not detached in some examples, and 

 detached and produced in others, and generally more strongly 

 sculptured than the penult and other whorls, with a well-pro- 



