24 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



arising from an expanded basis are also implanted very irregularly on this portion, 

 the calcareous matter of the lamella thickening sometimes and forming spines of 

 different length, sometimes isolated, at other times united in clusters of two, three, and 

 four, all directing themselves towards the exterior of the spire, and in general horizontally 

 to it, rarely exceeding in length the width of the lamella ; but in some cases they are a 

 third longer, being of greater length and more numerous towards the centre of the spinose 

 portion: fig. 18 illustrates a correct and considerably magnified fragment of the spire. 

 Professor Owen thinks they are calcareous excresences destined to support the Cirri, and 

 in this view both Viscount D'Archiac and M. De Verneuil concur ; the presence of these 

 spines only on that portion of the spine most exposed to currents, shows there was probably 

 greater strength and development of calcareous matter required in this portion of the spire. 

 The fact of the presence of spines, in a similar position, is common to many braclnopoda. 

 I have seen them in Spirifer rostratus, Walcotti Munstcrii, Terebrahda resupinata, Ter. 

 pectunculoides, &c, and in no specimens do they extend to the other portions of the spire. 

 The spirifer which Zieten considers to be Sowerby's Spirifer penguis, and figured 

 in his plate 38, fig. 5, is from the lias of Vachengen, and seems only a variety of 

 Sp. rostratus, and has much resemblance to the variety figured in my Plate II, figs. 7, 8, 9. 

 However, the name of penguis would require to be dropped at any rate, because 

 Sowerby's Sp. penguis is a Carboniferous shell, completely different from the Lias shell in 

 question ; M. D'Orbigny does not seem to have paid much attention to this point, as he 

 adopts the term penguis for a Lias shell. The Sp. rostratus has a wide range in the liasic 

 deposits, and has been found in the lower, middle, and upper lias, but chiefly in the marl- 

 stone of the middle Lias : fig. 4 is the only specimen as yet found by Mr. Moore in the 

 upper Lias of Ilminster, and there exists no well authenticated instance of a Spirifer occurring 

 higher up in the series in England. This species is found in many localities, such as Urn 

 Hill, Feavington, and South Petherton, near Ilminster, near Bath, Radstock, Cheltenham, 

 &c, and many fine specimens exist in several collections, especially that of Mr. Moore. 

 On the Continent it is also abundantly distributed ; in many parts of France, particularly 

 in Normandy, near Caen, round Avalon, at Boll ; in the Wurtemberg, near Amberg, in 

 the Canton of Basle, &c. And M. De Verneuil has lately brought it from the province of 

 Ferusil (Spain) ; it is also found in America. 



18. Spirifer Ilminsteriensis, Dav. 1851. Plate III, figs. 7, la. 



Diagnosis. Shell inequivalved, rounded, mesial fold and sinus hardly perceptible; 

 exterior of valves smooth, punctuated, and spinose ; beak of large valve much produced, 

 projected backwards at right angles with the smaller valve ; area very large, triangular. 

 Length 2, breadth 3, depth 2 lines. 



Obs. This little species was discovered by Mr. Moore, in the Leptaena or lowest beds 



