ATHYRIS. 79 



Loc. Sowerby states he obtained liis specimens from decomposed mountain 

 limestone (rotten stone), near Bakewell. The shell is far from rare in the lower 

 Carboniferous limestone of Derbyshire ; the Isle of Man ; Lowick, Northumberland ; at 

 Bolland, &c. In Scotland it is rather common in the Carboniferous limestone and shales of 

 the Clydeside basin, at Carluke, Lowrieston,^ at Westlothian ; Beith, Ayrshire ; and 

 Berwick-on-Tweed. In Ireland it is mentioned as occurring at Millecent, Kilcummin, and 

 Ballintrillick. On the Continent M. De Koninck states it to be rather rare at Vise, in Belgium; 

 and M. de Verneuil and Count Keyserling mention Peredki and Valdai as Russian localities. 

 In the United States it has been discovered at Chester, Illinois ; and in other localities. 



Athyris lamellosa, VJEveille. PI. XVI, fig. 1, and PI. XVII, fig. 6. 



Spieifee lamellosus, LeveilU. Memoires de la Soc. Geo), de France, ii, p. 39, figs. 21 — 23, 

 1835. 

 — SQUAMOSA, Phillips. Geol. of Yorks., ii, p. 220, pi. x, fig. 21, 1836. 

 Terebratula lamellosa, De Koninck. An. Foss. de la Belgique, p. 299, pLxx, fig. 5, a, 



h, c, 1843. 



Spec. Char. Transversely elliptical, or obscurely pentagonal ; valves moderately convex, 

 somewhat depressed ; cardinal line nearly straight. The mesial fold is of small elevation 

 and at times slightly concave along its middle. In the ventral valve a sinus of moderate 

 depth extends from the extremity of the small incurved beak to the frontal margin ; 

 foramen small, circular, and contiguous to the umbone of the opposite valve. Surfaces of 

 both valves ornamented by from twelve to fifteen nearly parallel concentric lamelliform 

 expansions. In the interior the spiral coils fill the greater portion of the shell. 



Length 14; width 21, depth 8 (without the expansion). 



Obs. This species was correctly described and illustrated by L'Eveille and Professor 

 De Koninck, who observe that its principal character resides in the presence of strong 

 concentric lamelliform expansions ; but this peculiarity is also common to other species of 

 At/i?/ris, such, as A. planosulcata, to which L'Eveille's species sometimes nearly approaches. 



Terebratula, Atrypa, Cleiothyris, Athyris, and Spirigera ! and it is to be regretted that those 

 who were discussing Professor Phillips's name on his half-announced views, had not inquired from 

 the author why he had conceived the group and name. On the Continent, D'Orbigny's term Spirigera 

 is generally preferred to that of Athyris, and I would myself have adopted the French author's 

 denomination, since it is freed from the incorrect derivation the term Athyris conveys, had I not found 

 that English authors were so much disposed to prefer M'Coy's name on account of its priority of 

 date. 



^ It may remain a matter of some uncertainty whether the representation given by David Ure, in 

 pi. xvi, fig. 9, of his ' History of Rutherglen' (1893), was intended for Ter. hastata or for the shell under 

 description ; but from the greater abundance of Sowerby's Ambignus in the district, I should almost feel 

 disposed to refer the figure above mentioned to the last-named species. 



