26 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



20. Spirifer Munsterii, Lav. 1851. Plate III, figs. 4, 5, 6. 



Spirifer octoplicatus, Zieten. (non Sow.) 1832. DieVerst. Wurttemb., pi. 38, fig. 6. 



— — Dav. 1847. London Geol. Journal, pi. 18, figs. 11— 14. 



Spiriferina — VOrb. 1849. Prodrome, vol. i, p. 221. 



Diagnosis. Shell inequivalved, variable, with elevated rounded mesial fold in small 

 valve, with corresponding sinus in larger one, with four, five, or six plaits on each side 

 of the mesial fold and sinus; beak more or less produced or recurved, elevated or 

 projected backwards ; area well defined, with deltidium in two pieces ; interior of both 

 valves similar to that seen in Sp. rostratus, Walcottii, &c. ; surface punctuated and spinose. 

 Dimensions variable, the largest specimen known measuring — length 15, width 14 lines, 

 but commonly does not attain that size. 



Obs. Many persons, as well as myself, have fallen into the error of attributing this 

 species to Spirifer octoplicatus, of Sow., M. C, vol. vi, table 562, figs. 2, 3, 4, 1829, 

 which name was given by that author to a Carboniferous species, much resembling our 

 Liasic one. Zieten appears to have principally led to this mistake, (Die Vers. Wurt., 

 1832,) and it has also been referred by some Palaeontologists to Spirifer acuticostatus, a 

 name given by Minister to a shell in the collection of Beyruth, and reproduced by Bronn, 

 along with many others, in 1840, without description or figures, so that it is impossible to 

 say what shell was intended, and no species can be admitted on such uncertain grounds. 

 In 1844 this name, accompanied by a figure and description, was given by M. de Koninck 

 to a mountain limestone species, which name Bronn places first, in page 1172, of his 

 ' Index Palaeontologicus.' Spirifer Munsterii is a very variable shell, as may be seen from 

 three specimens in Plate III, and is found along with Sp. rostratus in the marlstone of 

 Ilminster, and in many localities abroad, such as Pontaine-etoupe-Four, near Caen, &c. 

 Plate III, fig. 4, illustrates the largest specimen I have seen, found by Mr. Moore, near 

 Ilminster; figs. 5 and 6 is the common state in which it occurs. It much resembles 

 Spirifer cristatus of the Permian deposits : the tubular spines which cover its surface are 

 stronger, and considerably more numerous, than those observable in Sp. rostratus. They 

 are also visible on the portion of the spine facing the front, as in the above-mentioned 

 species. 



Genus — Terebratula, Lhwyd. 1698. 



Shell inequivalved, equilateral, more or less elongated, transverse or circular ; exterior 

 smooth, rarely striated or plicated ; larger valve convex, except in Ter. Eugenii, where it 

 is depressed or slightly concave ; with or without a sinus, corresponding to a mesial fold 

 in smaller valve, front straight or sinuated; beak straight or recurved and produced, 



