. The Canadian journal of industry, science and art. 336 T^E DBVONIAN FOSSILS OF CANADA WEST. Strophomena rhomboidalis.—(Wahlenburg). Lept^na depressa + Strophomena depressa + Lept^ena RUGOSA + Strophomena rugosa + Lept^ena tenuistria- ta? + Prodtjcta depressa + P. ANALOGA, &c. Either wholly or in part, of the generality of authors.*. Fig- in. Fig. 111.—Strophomena rhomboidalis, with the front straight. Fig. 112.—The same with rounded front. Description.—^Rhoraboidal or irregularly semi-oval, widest on the hinge-line, occasionally somewhat square: visceral disc strongly corrugated by from
. The Canadian journal of industry, science and art. 336 T^E DBVONIAN FOSSILS OF CANADA WEST. Strophomena rhomboidalis.—(Wahlenburg). Lept^na depressa + Strophomena depressa + Lept^ena RUGOSA + Strophomena rugosa + Lept^ena tenuistria- ta? + Prodtjcta depressa + P. ANALOGA, &c. Either wholly or in part, of the generality of authors.*. Fig- in. Fig. 111.—Strophomena rhomboidalis, with the front straight. Fig. 112.—The same with rounded front. Description.—^Rhoraboidal or irregularly semi-oval, widest on the hinge-line, occasionally somewhat square: visceral disc strongly corrugated by from nine to fifteen deep undulating concentric wrin- kles ; both valves abruptly bent at one-half or two-thirds the length to form a broad margin deflected towards the dorsal side. In the ventral or convex valve the disc is nearly flat, but with a small portion in front of the beak gently tumid. The curvature of the dorsal valve conforms very nearly to that of the ventral. Area of ventral valve narrow, seldom exceeding half a line in width ; the dorsal area still narrower ; the two areas inclined towards each other at an angle which varies from 30° to 60°. Foramen of ventral valve large, triangular, wider than high, partly filled by the two projecting extre- mities of the divaricator processes of the dorsal valve. Surface covered with fine crowded strise of a nearly equal size throughout, five or six in the width of one line. In the interior of the ventral valve the muscular impressions occupy a subcircular cavity which is about one-third the length of the valve and is bordered by an angular slightly elevated margin. The divari- ? Prof. Hall is desirous of having this species called S. rugosa, and says that he has seeti specimens of it labelled under that name in Rafinesque's hand-writing. But according to the laws of scientific nomenclature, manuscript names cannot be recognized at all. The first published specific name is {rhomboidalis), and this must be retained. The f
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