140 BRITISH CARBONIFEROUS BRACHIOPODA. 



projecting beyond the hinge-line; ears small, flattened, and from which project numerous 

 long slender spines ; surface covered with fine, thread-like, waving, radiating striae, which 

 increase in number at variable distances from the beak by the interpolation of other striae. 

 Spines few in number, and irregularly scattered over the surface. Dorsal valve concave, 

 following the curves of the opposite one, and similarly ornamented. 



Dimensions very variable ; three British specimens have afforded the following measure- 

 ments : 



Length 39, width 20 lines. 



,, 20, ,, 2b ,, 

 Obs. This species is very remarkable, on account of the various forms it is capable 

 of assuming, and has consequently not only been attributed to seven different genera, 

 but has received as many specific denominations. The shell and its history have 

 been minutely described by Professor de Koninck, as well as by some other authors, 

 but it was Lister who, in 1688, first noticed the shell, 'Hist, sive Synops. Conch.,' pi. 

 468, fig. 27 ; although it received its first specific denomination from Fischer de Waldheim 

 in 1830, or shortly after. The shell is sometimes so very irregular in its shape as to be 

 hardly recognisable, and although Professor M'Coy states that he has seen some Irish 

 specimens one foot in length by five inches in width, I have never observed any examples 

 exceeding four inches in length. The space between the valves is also remarkably small, 

 and in no case have I ever noticed an area in either valve. In 1840, Mr. J. de C. Sowerby 

 confounded some specimens of the shell under description with a distorted imperfect valve 

 of Streptorhynchus crenislria, var. senilis, and consequently erroneously described the 

 species as possessing a large triangular hinge area. Mr. Morris has also fallen into the same 

 mistake, for he classes Fischer's species in the sub-genus Strophalosia ; the reader is however 

 referred to p. 126 of the present monograph for further information upon the subject. The 

 spines are very numerous and closely packed upon the ears, Professor de Koninck having 

 counted as many as twenty-four on each of the auriculate expansions in certain specimens, 

 but that they are exceedingly rare on the surface of the shell. I have never seen any 

 perfect interiors of either valve, but fragments have shown that the details are very similar 

 to those of other species of the genus. 



In England it occurs in the lower scar limestone of Settle, in Yorkshire ; the lower 

 carboniferous limestone, Park Hill, Longnor, in Derbyshire ; the dark middle limestone of 

 Lowick, Northumberland, as well as of the Isle of Man, &c. No specimen has been 

 hitherto found in Scotland, and although Ardagh in Ireland is mentioned in Mr. 

 Kelly's list, I have seen no specimen. In Belgium it occurs at Vise. In Russia, 

 in the valleys of Stolobenka and Prikcha (Valdai) in the Petschora, near Zvenigorod, &c. 

 In the Punjaub (India), &c, &c. 



