RHYNCHONELLID^. 



159 



Stricklandinia lirata, ./. de C. Sow. (sp.). PI. XX, figs. 1 — 13. 



Spirifer liratus, J. de C. Sowerby. Sil. Syst., pi. xxii, fig. 6, 1839. 



Cardium multisulcatum, Hisinger. Lethsea Suecica, Supplementi secundi continuatioj 



p. 4, pi. xli, fig. 3, a, b, 1842. 

 Spirifer ovatus, MCoy. Sil. Foss. Ireland, p. 37, pi. iii, fig. 24, 1846. 



— MUITISULCATUS, Be Vemeuil. Bull. Soc. Geol. France, 2nd ser., vol. v, 

 p. 347, 1848. 



Orthis lirata, Phillips and Salter. Mem. Geol. Surv., vol. ii, part 1, p. 291, 1848. 

 Pentamerus liratus (Spirifer ovatus, Jl'Coy), Salter, in Morris's Cat. Brit. Foss., 



p. 142, 1854. 



— — Salter. Siluria, 2nd edit., pp. 100 and 230, fig. 3, 1859. 



— — Id. Mem. Geol. Surv., vol. iii, p. 360, 1860. 

 Ctrtina? multisulcata, Lindstroin. Pro. Roy. Acad. Stockholm, p. 360, 1860. 

 Stricklandia lirata, Billings. Canad. Nat. and Geol., vol. iv, p. 434, April, 1859; 



Canad. Palaeozoic Foss., vol. i, p. 84 ; Stricklandinia, Ap- 

 pendix, p. 419, 1865. 



Stricklandinia — Id. Catal. Sil. Foss. Anticosti; Report Geol. Surv. Canada, 

 p. 45, 1866. 



Spec. Char. Generally transversely oval, sometimes longer than wide and ovate, or 

 as wide as long ; hinge-line nearly straight and shorter than the width of the shell ; 

 cardinal extremities angular ; sides and front rounded. Valves almost equally and 

 moderately convex, never gibbous. Dorsal valve more or less semicircular and trilobed, 

 from the presence of a rather wide mesial fold of small elevation, which, commencing at 

 the extremity (^f the umbonal beak, gradually widens as it approaches the front. Ventral 

 valve with a wide shallow mesial sinus, originating at the extremity of the beak, and 

 widening as it approaches the rounded front ; beak small, incurved ; area narrow, with a 

 triangular fissure in the middle. Surface of valves ornamented with mmierous angular, 

 irregular, often bifurcating ribs, and concentric hues of growth. Inside the ventral valve 

 an exceedingly short vertical septum supports a small wide triangular chamber, formed 

 by the quickly converging dental plates. Inside the dorsal valve there is a narrow hinge- 

 area, with a triangular depression in the middle, formed by two small rapidly converging 

 (but not united) socket-plates, the inner extremities of which are prolonged into free, 

 narrow, crura, sometimes three and four lines in length. Under these, near the umbo of 

 the shell, are two elongated pear-shaped impressions, due to the adductor or occlusor 

 muscles, divided in the middle by a central ridge. Numerous pits (rough tubercules on 

 the cast), probably ovarian markings, surround these scars. Three specimens measured — 

 Length 2 inches 4 lines, width 2 inches 5 lines, depth 1 inch 1 line. 

 » 3 „ 1 „ „ 2 „ 8 „ 



