SPIRIFERINA. 19 



Spiriferina multiplicata, /. de C. Sowerby. Plate I, figs. 41 — 44. 



Spirifer multiplicatus, J. de C. Sowerby. Geol. Trans., 2d series, vol. iii, p. 119, 



1829 ; but described and illustrated for the first time by- 

 Professor King, p. 129, pi. viii, figs. 15 — 18, of his Mono- 

 graph of English Permian Fossils, 1850. 

 — — var. Jonesiana, King. Mon., p. 129, pi. viii, fig. 19. 



Shell small, rarely exceeding 5 lines in length, by 6 in breadth and 4 in depth ; is 

 more or less transversely oval, and often very much rounded in outline ; valves convex, and 

 sometimes much inflated. The hinge-line is shorter than the width of the shell; beak 

 more or less produced, elevated, and incurved ; area triangular, slightly concave, and 

 varying in dimensions (PI. I, fig. 44 1 ) ; fissure wide, and partially covered by a pseudo- 

 deltidium. From the narrowness of the area, the sides of the beak are more or less visible, 

 as well as its incurved extremity. The ribs are small, rounded, and rarely exceeding ten 

 in number ; mesial fold not much produced, and either rounded or flattened along its crest. 

 The sinus in the ventral valve presents a moderate depth, and the entire surface of the 

 shell is covered by numerous concentric laminae or ridges of growth ; shell-structure per- 

 forated ; the canals are (stated by Mr. Howse to be) smaller than those in Sp. cristata. 

 The internal details, according to Mr. Kirkby, differ a little from those already described 

 in the preceding species ; the whorls of the spiral are not so numerous, the spirals are not 

 so obliquely placed, and the first branch of the coil is not so angulated. 



I have felt considerable uncertainty as to whether the present shell should or not be 

 considered specifically distinct from Sp. cristata. Some authors, while admitting the 

 relationship existing between the two, are still of opinion that they should not be united, 

 on account of the smaller dimensions of Sp. multiplicata, its rounded outline, more 

 elevated and incurved beak, smaller and less angular ribs, and proportionately wider and 

 more flattened mesial fold. That, on the contrary, Sp. cristata is more acutely triangular, 

 the beak less elevated, the ribs more numerous, their sharpness and depth greater, and 

 the intimate shell-structure somewhat different ; but, after a minute examination of a very 

 numerous series of both, I found that, although many examples of the shell under descrip- 

 tion were easily distinguishable from S. cristata by the means of the characters above 

 specified, a great number left me in much uncertainty as to which of the two they in 

 reality did belong, for many individuals possessed the same number of ribs, and the other 

 distinctive characters became also much attenuated in their respective values. Professor 

 King allows me to state that he now begins to think that Sp. multiplicata may perhaps be 

 a variety of cristata, an opinion in which I entirely concur ; but, as some uncertainty still 



1 This remarkable specimen, from Tunstall hill, forms part of the collection of the Geological Survey 

 of London. It measures — length 6h, width 6, and depth 6 lines. 



