124 



base, and more or less distinctly shouldered or excavated, but not 

 angular above ; umbilicus small, but apparently never quite closed. 

 Aperture sub-eemicircular, pointed above, longer than wide, nearly 

 straight, or with a slight sigmoid curve on the inner side, and regularly 

 convex on the outer. 



Surface nearly smooth, but marked with minute, densely crowded 

 striae of growth in well preserved individuals. 



Length of the largest specimen yet obtained, six lines and a-half; 

 height of the spire, two lines and a-half; maximum width of the body 

 whorl, about five lines. 



Productive Coal Measures, Division A, of Nanaimo Eiver, Y. I., two 

 miles and a-half up, and of the Sucia Ishmds; J, Eichardson, 1872 and 

 1874. One imperfect example from the first mentioned locality, and 

 four well preserved specimens from the second. 



Gyrodes excavata, Michelin. (Sp.) 



Plate 16, figs. 2 and la. 



Naiica excavata, Mich., D'Orbigny.—'P&\. Franc, Terr. Cret., Vol. II., p. 155, Atlas 



pi. ITS, figs. 1 and 2. 

 Natica infracarinata, Qabb. — Proc. Ac. Nat. Sc. Phil., 1861, Vol. XIII., p. 319. 



Oyrodes Spillmanii, Gabb. — Idem, p. 320. 



Shell depressed subgloboso, about as wide as high, spire short, less 

 than one-fourth the entire length. Whorls four, those of the spire 

 obliquely and gently convex, the third being also distinotly truncate 

 above. Body whorl truncated nearly horizontally next the suture, 

 concavely constricted immediately below the angle, which is subacute, 

 and swelling out widely near or a little below it ; base obliquely and 

 somewhat concavely truncated on the inner side. Umbilicus widely and 

 deeply ftmnel-shaped, with a distinctly carinated margin. Aperture 

 ti-iangular above, pointed below, longer than wide ; outer lip thin, 

 simple, and expanded in tlie centre; inner lip nearly straight, but 

 curved somewhat concavely below. The truncation of the whorls above 

 \i concave in some specimens and flat in others. 



Surface polished, nearly smooth, but marked with minute, numerous, 

 and densely arranged curved striae of growth. 



The length and breadth of a perfect specimen are almost exactly equal, 

 the greatest diameter being about six lines and a-half in either direction ; 

 the height of the body whorl is five lines. 



Middle Shales, Division D, north-west side of Hornby Island, (one) ; 



