THE NAUTILUS. 115 



and is of a light greenish-yellow and much more globular than the 

 others and barring the bands, which are three instead of two as 

 called for by the original description, has great resemblance to A. 

 globula of Lea. The aperture is almost exactly two-thirds of the 

 length of the shell. Among a small set from the Holston at Knox- 

 ville, Tennessee, collected by Mr. A. C. Billups, are larger speci- 

 mens (10x8.5 mm.) of the same form, but I have been unable to 

 trace it with entire satisfaction to maturity. It is, however, appar- 

 ently the immature form of the species that Dr. Lewis identified with 

 the A. virgata of Lea. But whatever the relation of the form to 

 subglobosa may be, it agrees with it in its smooth, shining, rounded 

 whorls with no impressed spiral lines and no carinae. 



III. A. TINTINNABULUM Lea. 



Dr. Lewis' series of this species is very complete and as he states, 

 there can be no question but that the bicarinate form that he identi- 

 fied with Lea's cincinnatiensis is the young of tintinnabulum. But 

 they are quite different from the true cincinnatiensis if I am right in 

 my identification of that form, and seem to be specifically distinct. 

 Compared with cincinnatiensis of the same size, these shells (Figs. 7 

 and 8) have a more elevated spire and are much thicker, being quite 

 opaque and noticeably more heavily moulded ; the surface of the 

 whorls above the superior carina is decidedly convex above and 

 excavated below as it approaches the carina, so that on the third and 

 fourth whorls there is a well-developed groove immediately behind 

 the carina ; the carinae are much stronger, the superior projects 

 upwards rather than laterally, and is formed more by the excavation 

 of the upper surface of the whorl behind the uplift of the intercari- 

 nal area, than by the lateral projection of the carina, as in cincin- 

 natiensis ; the lower carina is much stronger and projects laterally ; 

 the intercarinal area is relatively wider and very flat, being scarcely 

 at all concave ; the basal area is much more excavated immediately 

 below the inferior carina. While color is, perhaps, the least re- 

 liable factor in specific distinction in Anculosa, in this series it is 

 remarkably uniform and very striking. The shells are uniformly 

 light greenish-yellow with two broad reddish-brown bands on the 

 body whorl, one above the superior carina and the other on the basal 

 area immediately below the inferior carina ; the apical whorls are 

 reddish-brown ; the intercarinal area has no band, the carin* are 



