40 BRITISH CARBONIFEROUS BRACHIOPODA. 



to institute between them a minute and searching comparison, which enables me to substan- 

 tiate to a large extent the opinion expressed by Baron Von Buch and Professor King as to 

 the close resemblance existing between the Carboniferous and Permian shells, and to 

 declare that, in my humble opinion, Sp. odoplicata cannot claim to be considered more 

 than a variety of Sp. cristata} 



The discovery lately made by Mr. Kirkby, at Tunstall Hill, of a magnificent and 

 unusually large example of Schlotheim's species (first illustrated by Mr. Howse in the 

 ' Annals of Nat. Hist.,' 2 and subsequently more fully so, during the same year, in PI. II, 

 fig. 43, of our Permian illustrations), places this matter beyond even the range of doubt; 

 for, with the dimensions of 5 lines in length, 9^ in width, and 5 in depth, a mesial fold, 

 of which the crest is depressed towards the front, and fourteen ribs on each valve, it pre- 

 sents all the characters and appearances of several of Sowerby's type examples, from which 

 it is distinguished only by the light-yellow colour peculiar to our Permian fossils. I 

 feel, therefore, disposed to maintain for the Carboniferous shell the varietal designation of 

 odoplicata, to distinguish it from Schlotheim's type, which is, in general, of smaller 

 dimensions, with a minor number of plaits. The variety odoplicata has likewise shown 

 a tendency to triplication in the mesial fold, which I have not hitherto observed on any 

 of the numerous individuals of the Permian shell that have passed under my notice. 

 From Sp. laminosa the shell under description is easily distinguished by its less numerous, 

 comparatively larger, and more angular ribs ; from Sp. insculpta (a closely allied form) by 

 the greater disproportion of the mesial plait relative to the lateral ones, which are, at the 

 same time, more numerous and smaller in Sowerby's shell. I am still uncertain 

 whether Sp. minima (Sowerby) and Sp. partita (Portlock) should be considered as 

 specifically distinct, or forming part of the variety of Sp. cristata. The material in my 

 possession has not been sufficient to allow me to determine that point satisfactorily. 



Loc. Sowerby mentions his specimens as having been derived from Derbyshire. Gare, 

 Lanarkshire ; Dr. Fleming has examples from Westlothian, Scotland ; and a fine Irish series 

 from Hook Point and the shores of Lough Hill, county of Sligo, may be studied in the 

 Museum of the Geological Society. Professor M'Coy mentions the shell from Flintshire, 

 and Mr. Kelly quotes Bundoran, Carrowmably, and Cregg, Ireland. It has also been 

 found in several foreign localities. 



Spiriferina minima, Sowerby. Plate VII, figs. 56 — 59. 



Spirifer minimus, Sowerby. Min. Con., p. 105, tab. 377, fig. 1, Nov., 1822. 

 Spec. Char. Rhomboidal, a little wider than long ; hinge-line rather shorter than the 



1 As Sp. odoplicata was first introduced into existence, and therefore the oldest form, it is in 

 reality the type of which Sp. cristata would be the variety, but the law of priority as to names obliges 

 us to retain Schlotheim's in preference. 



2 Vol. xix, 2d series, pi. iv, figs. 5 and 6, 1857. 



