STROPHOMENID.E. * 285 



Wenlock Edge ; Baildwas ; The Rock, May Hill ; Woodgreen, Longliope, Beacon Hill 

 Quarry, Sedgley; Dormington Wood, Woolhope. 



In the Ludloio series : at Vinnal Hill, Ludlow, and Freshwater East ; also in many 

 localities (recorded by Phillips and Salter) in the Malvern, Abberley, Woolhope, May 

 Hill, Tortworth, Usk, Builth, and Marlow districts. 



In Scotland it occurs at Craig Head (Caradoc), and at Penkill and Mullock Hill, 

 Ayrshire, in Llandovery rocks. In the Pentland IliUs it is common in Wenlock Shales. 

 In Ireland it is also found in the Caradoc of the Chair of Kildare ; in Wenlock Shales at 

 Ferriter's Cove, Dingle, County Kerry ; and in a number of other localities, which will 

 be found recorded at p. 25 of M'Coy's ' Sil. Foss. Ireland.' 



Abroad it is very abundant in many Lower and Upper Silurian localities. It occurs 

 in Gothland, Ostrogothia, Norway, Bohemia, Belgium (Gembloux), Russia, the Island 

 of Anticosti, Canada, the United States, &c. 



Strophomena ungula, irCoy (sp.). PI. XLII, figs. 20 and 21. 



Lept^na (Leptagonia) ungula, M'Coy. Ann. Mag, Nat. Hist., ser. 2, vol. viii, p. 



404, 1851 ; and Brit. Pal. Foss., p. 249, pi. i H, 

 figs. .S6 and 37, 18.52. 

 — — — Salter. Siluria, 3rd edition, pi. 543, 1859. 



Sjjec. Char. Semi-oval, or slightly sub-quadrate, wider than long ; hinge-line 

 quite as wide as the shell ; cardinal extremities almost rectangular ; sides straight, and 

 sub-parallel for half their length, then rounding into the convex frontal line. Ventral 

 valve nearly flat, or very slightly convex until it nears the margin, when it becomes 

 suddenly deflected to the margin. Area triangular, rather narrow ; fissure arched over 

 by a pseudo-deltidiura ; beak not projecting. Dorsal valve slightly concave, following the 

 curves of the opposite valve ; hinge-area linear. Surface of valves marked by a few 

 concentric wrinkles (more apparent in some specimens than in others), and ornamented 

 by numerous fine thread-like radii, with finer longitudinal lines in the interspace left 

 between each two of the principal ribs. In the interior of the ventral valve the saucer- 

 shaped muscular cavity is small, and longitudinally divided along the middle. Interior 

 of dorsal valve not known. 



Length 9, width 10, depth 1^ lines. 



Ohs. Prof. M'Coy observes that " This so nearly resembles some of the small 

 varieties of Leptoena deltoidea and the L. earner ata (Conrad), as figured by Hall, that 

 I should not have thought of separating them were it not for the very much finer striae, 

 which very easily separate the species from our British specimens of L. deltoidea. The 

 foramen of the apex of the beak is also larger, the dental lamella more divergent, and 



