58 BULLETIN 164, UNITED STATES NATIONAL MUSEUM 



a peripheral band. The whorls are about two times greater than 

 their length, uniformlj' rounded, and enlarge gradually. In a frag- 

 ment of a larger specimen the largest well-preserved whorl, next the 

 body wall, has a width of 20 mm, and a vertical height of 10 mm. 

 The extent of embracing is slight, producing a loose-coiled shell with 

 a deep suture, which is oblique and forms an angle of about 70° with 

 the axis of the shell. Aperture subovate; umbilicus comparatively 

 small. 



Comparisons. — This species appears to be relativel}'^ close to Eor- 

 motoiiia terehri fortius Foerst€, an American species from the Trenton 

 group, Rogers Gap, Ky., but it is readily distinguished by the feeble 

 angulation on the surface and the deep suture. 



Formation and locality. — Middle Ordovician, Ssuyen formation: 

 Lower fossil horizon of the black banded limestones, 1.5 miles north 

 of the Pen-hsi-hu collierj'^, Liao-tung. 



Holotype.—U.S.'^.M. No. 83663. 



HORMOTOMA species undetermined 



Plate 32, Figures 1-4 



Several casts of a gastropod (U.S.N.M. No. 83664), which from 

 the general form of the spire and the contour of the whorls is refer- 

 able to the genus Hormxytoma^ were obtained from the Santao forma- 

 tion in Manchuria. 



Description. — Height averages 30 mm, apical angle about 12°. 

 Specimens comparatively small, slender; whorls are somewhat de- 

 pressed ventricose. Volutions eight in a specimen 36 mm long ; other 

 specimens consist of six whorls. The apical portion of all my speci- 

 mens is imperfect. The extent of embracing is slight, producing a 

 loose-coiled shell, with deep suture, which is very oblique and forms 

 an angle of 65° with the axis of the shell. 



On the surface of some casts a suggestion of a rounded peripheral 

 band may be seen, but it is not ver}^ distinct. Aperture round ; um- 

 bilicus closed. 



Comparisons. — This species may be related to the Hormotoma 

 artem^esia type from the Canadian strata of North America, but as my 

 specimens are too poor to identify with this or any other species, 

 they are simply referred to Hormotoma with the hope that better 

 specimens may be obtained in the future, when a specific name can 

 be assigned. 



Formation and locality. — Upper Canadian, Santao formation : In 

 the banded limestones near Shang-kang-yao, 3 miles southeast of 

 the Yen-tai colliery, Liao-tung, Manchuria. 



