TV I. Grabau Ordovician Fossils from North China (l) 25 



HOIUZON AND LOCALITIES; In the upper beds of the Machiakou or Actinoceras 

 limestone, at Tangshan in the Kaiping Coal Basin, Chihli province, T. C. Wang coll 

 Also in the same formation at Huo-Luh, (Hwo-Luh) Chihli, Miss Clarke, coll. 



Family PLEUROTOMARIID^E d'Orbigny 



Genus LOPHOSPIRA Whitfield 



Lophospira morrisi Grabau (sp. nov.) 



Plate III Figs. 1, 2a, b. 



Shell of medium size for the genus. Spire consisting of about five angular whorls 

 which embrace to within a very short distance of the peripheral carina. Apical angle 57 

 - 58 degrees. Whorls with flat or very gently concave shoulder, pronounced peripheral 

 carina, obtuse shoulder angle, and faint lower carina. In well-preserved specimens, the 

 shoulder angle is marked by a sharply rounded carnia with a narrow peripheral band on 

 the outer edge of the shoulder, delimited by the peripheral carina and a fainter spiral 

 above it. Lines of growth fine and sharp, beginning at the suture, where the shoulder is 

 sometimes thickened as by a faint subsutural carina. From this point the lines of growth 

 brnd backwards, at first very gently, then, as they approach the band, move abruptly, 

 crossing the band with a distinct semilunar curve. In this respect the growth-lines and 

 band are very similar to those of Liospira barbouri from the same horizon. They evidently 

 indicate a father pronounced supra-marginal notch, a feature mot usual in the genus 

 Lophospira where the notch is generally at the peripheral carina. 



The lower carina is faint and scarcely affects the contour of the body of the whorl; 

 it may indeed be absent altogether. 



Aperture sub-rhomboidal, the inner lip slightly reflected and covering the 

 umbilicus. 



Length of a perfect specimen (Plate III fig. 1), 17.5 mm., greatest diameter of 

 body whorl, 12.5 mm. 



This species is very similar to Lophospira medialia Ulrich and Scofield, from the 

 Trenton limestones of New York and the central United States, the chief difference being 

 the pronounced marginal band on the shoulder of the Chinese species, and its somewhat 

 sharper peripheral carina. In other respects the two species are closely allied, and some- 

 what worn specimens of the Chinese species might readily be taken for the American 

 form. 



