262 SYSTEMATIC PALEONTOLOGY 



Description. — "Shell depressed, with very fine transverse strife; sides 

 straight : whorls with a very slight obtuse elevation revolving immediately 

 above the suture ; apex acute ; aperture rhomboidal ; umbilicated. 



" The specimen from which the above description was taken exhibits 

 part of the original markings; a band of light-colored minute spots re- 

 volves near the suture on the large whorl; and another band of similar, 

 but larger spots revolves near the middle of the same volution ; tlie striai 

 are very strong on the base, particularly near the umbilical margin." 

 Conrad, 1830. 



The color pattern referred to by Conrad has been oljserved on a numl)er 

 of specimens. A specimen belonging to the Wagner Free Institute of 

 Science has three rows of spots, one just below the suture and two near 

 the center of the whorl. 



This is the most abundant species at St. Mary's Eiver. 



C. conus H. C. Lea differs from this species in being more elevated, in 

 having more convex whorls, and a rounded basal margin. 



Height, 13 mm. ; diameter, 20 mm. 



Occurrence. — St. Mary's Formation. St. Mary's Ki^er. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum, Philadelphia Academy of Xatural Sciences, 

 AVagner Free Institute of Science, Cornell University. 



Calliostoma reclusum (Conrad). 

 Plate LXI, Figs. 14a, 14b, 14c. 



Trochiis reclusua Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, 1st ser., p. 219, 



13l. ix, tig. 6. 

 Trochus reclumcs Conrad, 1843, Proc. Nat. lust.. Bull, ii, p. 187. 

 Zizyphinus redusus Conrad, 1863, Proc. Acad. Nat. Sci. Pbila., vol. xiv, p. 569. 

 Zizyphinus redusus Meek, 1861, Miocene Check List, Smith. Misc. Coll. (183), p. lo. 

 Calliostoma {Eutrochus) humilis Dall, 1893, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. ii, p. 405. (In part.) 



Description. — "Shell much depressed; transversely striated; whorls 

 flattened on the summit, with straight sides; aperture transversely ovate; 

 umbilicus profound, carinated and slightly funnel-shaped. 



" The carina within the umbilicus is visible on the two last whorls." 

 Conrad, 1830. 



This species is distinguished from C. hum He l)y the flat-topped, beaded 

 shoulflor of the whorls. 



