43 



five in two lines at the margin. There appear to be concentric striae 

 most distinct in the grooves between the ribs. Length 8 lines ; width 10 

 lines ; depth of both valves 4 lines. Gamache Bay ; Div. 1, A. G. T. 

 C. Weston. 



Genus Orthisina, D'Orbigny. 



0. Verneuili, Eichwald. — Gamache Bay ; Div. 1, A. G. Also in several 

 locahties in the Trenton limestone in Canada West. 



Genus Rhynchonella, Fischer. 



R. GLACiALis, B., op. cit., p. 143.— Gull Cape; Div. 2, A. G. 

 R. FRiNGiLLA, B., op. cit., p. 141. — Gull Cape ; Div. 2, A. G. 



R. Janea, n. sp. — Sub-ovate, apical angles about 80° ; sides somewhat 

 straight in the upper half, rounded in the lower half ; about one-half of the 

 front margin truncated or nearly straight. Ventral valve moderately 

 convex ; sinus deep and concave at the front, one-third the whole width, 

 dying out near the umbo ; sides of the sinus with one or two prominent 

 ribs from which there is a somewhat flat slope to the margin ; umbo prom- 

 inent but narrow ; beak elevated about half-a line above the hinge and 

 moderately incurved ; there appears to be a circular foramen beneath it. 

 Dorsal valve more uniformly convex than the ventral ; mesial fold dying 

 out at about two-thirds the length. There are four angular ribs on the fold 

 and three on the sinus ; from six to eight on each side or from sixteen to 

 twenty in all on each valve. Length 6 or 7 hnes ; greatest width about the 

 same. 



This species differs from R. Anticostiensis in having the beak more 

 incurved. Gamache Bay ; Div. 1, A. G. T. C. Weston. 



R. NUTRix, n. sp. — With the exception of the beak and a slight conca- 

 vity in the front margin the outline of this shell, on a dorsal view, is 

 nearly a perfect ellipse. In other respects it does not differ to any impor- 

 tant extent from H. Janea. Width 8 hnes ; length 6 lines. Gamache 

 Bay ; Div. 1, A. G. T. C. Weston. 



R ? ARGENTEA, D. sp. — Shell transversely ovate or sub-globular, propor- 

 tional length and breadth variable. Ventral valve strongly convex, most 

 elevated about the middle ; beak, apparently closely incurved ; mesial 

 sinus about one-third the whole width, dying out at the mid-length, abruptly 

 elevating the margin of the opposite valve. Dorsal valve rather more 

 strongly convex than the ventral ; a narrow groove extending from the 

 umbo towards the front most probably connected with an internal mesial 

 septum ; mesial fold short but strongly elevated, extending about half the 

 length. Surface with numerous small ribs or, rather, strice which appear 

 to bifurcate, three or four in the width of one line. Shell, in exfoliated 



