﻿JURASSIC AXD TRIASSIC BRACHIOPODA. 



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41. Spiriferina Muxsteri, Dav. Dav., Ool. Mem., p. 26. PI. Ill, figs. 4 — 6. 



Nothing new. It occurs in the zone of Am. margaritatus (Middle Lias), and in 

 that of Am. bifrons (Upper Lias). It is a smaller shell than Sp. orygona. I cannot agree 

 with Mr. "What ley, in considering it only a variety of Sp. Walcotti. 



42. Spirieerina Deslongchampsii, Dav. Sup., PI. XI, fig. 12. 



Spibiferixa Desloxgchampsii, Bar. Annals and Mag. of ^at. Hist., 2nd ser., vol. 



ix, pi. xv, fig. 4, 1S52. 

 — — E. Desl. Bull. Soc. Linn, de Normandie, vol. iii, 



pi. iii, figs. 12, 13, 1S59. 



Spec. Char. Shell wider than long ; dorsal valve semicircular, moderately convex, 

 mesial fold more or less defined, of small elevation. Ventral valve much deeper than the 

 opposite one ; beak rather large, straight or very slightly incurved, and at right angles 

 to the plane of the dorsal valve; sinus shallow, scarcely defined ; area triangular, flat, 

 fissure partly arched over by a narrow pseudo-deltidium ; hinge-line rather less than the 

 greatest breadth of the shell. Surface of both valves ornamented with from sixteen to 

 thirty rounded ribs, from which rise numerous small hollow spines ; the interspaces 

 between the ribs are comparatively smooth. 



Proportions variable ; width 15, depth 9 or 10 lines. 



Obs. When I described this species for the first time in the 1 Annals,' the dorsal 

 valve of a single French specimen had been obtained ; since then Mr. Eugene Deslong- 

 champs has been able to publish descriptions and drawings of the complete shell from 

 specimens obtained from the Middle Lias of Fontaine-Etoupe-Four, in Normandy. A 

 small number of very good examples were subsequently found by Mr. C. Moore in the 

 Middle Lias of Whatley, so that we are now in a position to completely illustrate this very 

 interesting species. The ribs are somewhat irregular in number and size, and in some 

 examples are hardly defined ; a few are sometimes bifurcate, or a shorter rib is interpolated 

 between two simple ones. 



43. Spirieerina Ilminstertensis, Dav. Dav., Ool. Mon., p. 24, PI. Ill, figs. 7, 7a. 

 Nothing new. It occurs in the zone of Am. bifrons in the Upper Lias. 



