INSTITUTE OF SCIENCE, PHILADELPHIA. 403 



The shell appears nearly smooth, with a narrow, deep umbilicus, and the 

 usual blunt, sometimes grooved, tooth at the end of the pillar. Under a glass the 

 spire is seen to be finely spirally threaded, the threads less numerous and more 

 distant in the early whorls. The base is spirally striate, with faint grooves or 

 impressed lines. The suture is obscurely channelled in the early whorls and 

 the periphery is rounded, the whorls slightly so. A well-grown specimen 

 measures 8 mm. high and 10.5 mm. in greatest diameter. It is sometimes a 

 little larger. In addition to the published synonyms, on one of Conrad's 

 manuscript labels in the National Museum collection this species is named 

 Zisypliinits mmylandiats. 



Calliostoma cyclus n. s. 

 Plate 23, figure 20. 



Miocene of the Natural Well, Duplin Co., N. Car., PVank Burns. 



Shell small, much depressed, but with a rather prominent apex and four 

 whorls ; early whorls with three or four strong, rounded spirals with narrower 

 interspaces, the periphery doubly keeled, but the keels, covered up in the 

 closely appressed suture ; later the suture falls below the upper keel, and 

 finally follows the lower one ; on the later whorls the upper keel is stronger, 

 but both are prominent ; the upper surface of the whorl is somewhat 

 excavated between the keel and the suture and is very sharply, almost micro- 

 scopically spirally striate, the striations crossed by obsolete incremental lines ; 

 base flattish, conical, spirally striate like the upper surface ; umbilicus narrow, 

 deep, funicular; umbilical rib formed of two close-set, stout spirals surrounded 

 by a sharp groove ; aperture subquadrate, oblique, wider than high, pillar 

 simple, straight, thickened toward the basal angle. Alt. 3.5 ; max. diam. 5.2 

 mm. 



This strongly-marked little shell is probably not fully adult, but its char- 

 acters cannot be reconciled with the young of any other species now known 

 The nearest form is C. arniillatuin, which has a moniliferous suture, the upper 

 surface of the whorls rounded or convex, the umbilical ribs conspicuously 

 beaded, and the spiral striation coarser, especially on the base. The adult 

 arinillatiivi is not keeled at the periphery, the young sometimes are, but the 

 keel is usually single, and when double not separated by a broad, distinct, 

 deep groove, as in the present form. 



Two specimens were obtained by Mr. Burns, the larger of which has 

 served as a basis for the above description. 



Calliostoma (Butrochus) jujubinum Gmelin. 

 C. jujubinum (Gmel.) Dall, Rep. on Blake Gastr., p. 369, 1889. 



Pliocene of the Caloosahatchie and Shell Creek, Fla., Dall and Willcox ; 

 recent on the southeastern coast of the United States from Cape Hatteras 

 southward, and throughout the Antilles, in moderate depths. 



