INSTITUTE OF SCIENCE, PHILADELPHIA. 399 



Patuxent, Md.," but belonging to an entirely different species from Wagner's 

 shell, and really Eocene. 



It is probable that even Conrad never perpetrated more numerous blun- 

 ders in so few lines of text as in the present case. The diagnosis, judged by 

 the species grouped under it, is absurd. None of them has two denticles 

 on the columella; Omphalius kiahwahensis is not polished and has a wide 

 umbilicus; Leiotrochus distans, in Conrad's own words, has it " narrow, pro- 

 found." Nothing is known of the umbilical characters of the unpolished 

 non-denticulate Turbo caperatus, and Monilea eborea Conr. {iion Wagner) has 

 a deep pit, though not a perforation or a denticle. Trochus eboreus Wagner 

 has no umbilicus. None of the species belong to the genus Monilea Swain- 

 son, while Conrad's own type is placed by him both in Monilea and Fossarus. 



Notwithstanding all this, if we eliminate the true Trochus eboretcs Wagner 

 {lion Conrad), there is a superficial similarity between the shells Conrad 

 grouped together ; they are without strong sculpture, are turbinate rather 

 than trochiform, mostly have some obscure callosity on the pillar, and in 

 general outline have a certain similarity to the shell figured by H. and A. 

 Adams as an example of Monilea. However, the group cannot be con'sidered 

 as a natural one, and must stand or fall by its original sole species and type, L. 

 distatis. If I am correct in identifying this (in the absence of the type and 

 without any figure) with the shell subsequently named Briani by Conrad — that 

 is, simply a small species of Calliostoma of the section Eutrochus Adams — 

 while the name Leiotrochus has a few months' priority over Eutrochus, the 

 doubts which hang about it seem to the writer to make it inadvisable to adopt 

 the former as a substitute for the latter. If others take the same view, the 

 name Leiotrochus will simply fall into the synonymy of Calliostoma. 



Oalliostoma (eboreum Wagner var. ?) Wagneri Dall. 

 Plate 21, figure 3. 



Shell small, rather depressed, with a rather large, smooth nucleus and five 

 subsequent whorls ; surface of the shell smooth except for lines of growth ; 

 whorls at the periphery flattened, with two well-separated keels, the upper the 

 more prominent ; the- suture in the earlier whorls is applied to the upper keel, 

 but gradually recedes from it and runs about midway between them; imme- 

 diately in front of the suture the whorl shows a narrow, rounded ridge parallel 

 with the suture ; between this ridge and the upper peripheral keel the surface 

 of the whorl is excavated or impressed to an extent varying in different 

 specimens ; base smooth, umbilical region with a wrinkled callus, sometimes 

 bounded by one or two spiral grooves, but often without them ; pillar short, 

 thick, with an obscure denticle ; aperture subquadate, outer lip simple, throat 

 not Urate. Max. diam. of shell lo.o; alt. 8.5 mm. 



This interesting shell, obtained by Mr. G. D. Harris, U. S. Geol. Survey, 

 from the older Miocene of Greensboro', Caroline Co., on the " eastern shore " 



