SPIRIFERID^. 



107 



myself broken and sliced many specimens of different species which possess spiral 

 appendages before obtaining them. It is therefore not always safe to assert that a 

 species may not have possessed certain appendages because they are not exposed on 

 breaking a specimen. Now, in Nucleospira pisum they may often be seen without fractur- 

 ing the shell, through its transparent walls, as in the specimen fig. 18 of our Plate. The 

 interna] details of this species have been already given in full by Prof. Hall, in the generic 

 description, and consequently need not be again repeated ; but we must mention the long 

 hair-like spines which so closely cover the perfect shell ; and my attention was first turned 

 to this circumstance by Dr. Holl, who sent me a specimen so invested, which he had 

 discovered in the Wenlock Limestone of Colwall Copse ; and there are others preserved 

 in the Natural History Museum at Worcester. 



Position and Locality. Nucleospira pisim occurs in the Wenlock Limestone and 

 Shale of Hay Head, near Walsall ; Wren's Nest, Dudley ; and Benthall Edge, in the 

 Wenlock district; Colw^all Copse, Malvern; Dormington and Lindels, in the Woolhope 

 district. Under Worcester Beacon, in Woolhope Limestone. In Scotland internal casts 

 have been recently discovered in the Wenlock shale of the Pentland Hills, by Messrs. D. 

 J. Brown and J. Henderson, of Edinburgh. These I will figure in the Supplement. This 

 species has also been found in Gothland. Prof. Hall obtained it from Walcott, New York 

 State, in shales of the Niagara Group. 



Genus or Suh-genus Meristella, Hall, 1860. 



Kail. Thirteenth Report on the State Cabinet of New York, p. 73, I860.— Fifteenth 

 Report, &c., p. 179, 1862.— Sixteenth Report, &c., p. 50, 1863. 



I need not here repeat the reasons which induced Prof. Hall to propose the generic or 

 subgeneric designation of Meristella for shells typified by Atrypa timida of Dalman ; these 

 details are given in a foot-note in pp. 13, 14, and 15 of my 'Monograph of Devonian 

 Brachiopoda,' 1864. 



At p. 50 of the ' Sixteenth Report' Prof. Hall adds the following observations to those 

 he had published in 1860 :— "The genus Meristella includes Terebratuloid or Atlyroid 

 forms which are ovoid, more or less elongate, sometimes elliptical in outline, and not 

 unfrequently transverse or sub-circular; valves unequally convex, with or without a 

 median fold and sinus ; and this feature, when present, usually confined to the lower 

 half of the shell. Ventral beak more or less closely incurved (when closely incurved, 

 apparently imperforate), terminated by an aperture, the lower side of which may be formed 



