48 BRITISH PERMIAN BRACHIOPODA. 



peculiar. Its relationship to more than one Carboniferous species has also been noticed 

 both by M. De Verneuil, De Koninck, and others. 



There exists, perhaps, one or two varieties of Geinitz's Stroph. lamel/osa, which it 

 might be desirable to distinguish by varietal appellations ; ! but it would be incorrect to 



in length, by about the same in width. The larger or ventral valve is very convex 

 and swollen out posteriorly, without any mesial depression or furrow ; the lateral 

 slopes are rapid, and almost perpendicular to the back of the valve. The beak is 

 of moderate dimensions, rounded, and projecting but very slightly beyond the 

 cardinal edge. The hinge-line is straight, and a little shorter than the greatest 

 width of the shell, without area or hinge-teeth. The ear-shaped expansions are 

 small, and terminated by a peculiar angular plait. The outer surface of the larger 

 valve is covered by a great number of minute, irregular-sized striae, which are (The radiating striae have 

 simple or dichotomous, one, two, or more forming the elongated base of a spine ; not n sufficiently 

 these last are irregularly scattered over all the surface, at variable distances ; thos e ex P ressed in this cut.) 

 on the back are more sparingly distributed than on the ears, and project somewhat outwardly and down- 

 wardly ; but those on the lateral slopes are perpendicular to the striae. The spines on the cardinal region 

 and ears are quite erect, long, and so numerous that they completely conceal the surface of the shell. 

 The length attained by the spines on different portions of the valve is very variable ; some are of great 

 length, hollow, and ornamented by delicate rings. The smaller or dorsal valve is concave, following the 

 curves of the opposite one ; no area nor hinge-sockets are visible ; the surface is covered bv a multitude of 

 fine, slightly raised, radiating striae, and numerous wrinkles or lines of growth. This Productus was well 

 described by M. De Verneuil and Count Keyserling, as also by M. De Koninck, from the Permian beds of 

 Russia. The first two authors discovered it at Kicherma, on the river Wei ; and Ouchta, at Chidrova, 

 Arramas Ilschalki, Kidash Nikefur, Grebeni, &c. Dr. Schrenk found it at Ustj-joshuga, near Pinega, in the 

 Government of Archangel. Baron Schauroth obtained the same shell at Milbitz, in Germany ; and Professor 

 De Koninck describes the species from Bell Sound, Spitzberg ; but it has not hitherto been discovered in 

 our British Permian strata. 



1 In a very interesting paper published in the ' Annals and Mag. of Nat. Hist.' for March and April, 

 1856, Professor King describes his two varieties as follows : 



" Strophalosia Morrisiana, taking the Tunstall hill specimen as its type, may be described as follows : 

 General form flatly concavo-convex, transversely elliptical. Large valve slightly convex, evenly rounded, 

 often with one or more contracted longitudinal furrows ; wrinkles on the sides, and furnished with a num- 

 ber of long, rather distant, somewhat irregularly arranged creeping or adpressed spines directed forwards ; 

 both inner and outer surface marked with nearly obsolete striae, radiating from the umbone ; also with 

 numerous well-defined incremental lines. Umbone slightly affecting the even roundness of the valve ; 

 decidedly impressed or truncated, and scarcely converging down to the cardinal edge. Area a little more 

 in length than half the width of the valve ; rather low, but well defined, being in the form of a very obtuse 

 triangle, the sides of which are about equal to |ths of the length of the base ; faintly lineated transversely, 

 and furnished with a narrow deltidium. Small valve slightly concave, here and there exhibiting a few 

 nearly obsolete, slightly elongated, indented impressions, a little raised at their anterior end, which causes 

 them to appear as if produced by a blunt-pointed instrument ; both inner and outer surface marked with 

 fine radiating striae, a little more strongly marked than those on the large valve. Nucleus raised a little 

 above the general surface of the valve ; area little more than rudimentary. All the specimens I collected 

 of this species are a little under an inch in width, and about fths of an inch in length. The smaller valve, 

 I am strongly inclined to think, cannot be considered spiriferous ; probably the nearly obsolete indented 



