BRITISH DEVONIAN BRACHIOPODA. SB 



23. Spirifera Verneuilii, Murck. Dav.,Dev. Mon., PI. V, figs. 1 — 12; PI. VI, figs. 



1—5 ; and Dev. Sup., PI. II, fig. 1. 



At p. 23 of my ' Devonian Monograph ' I described this species by the name 

 disjuncta. Sow., but soon after discovered that Murchison's name Verneuilii held priority 

 over that given to the same species by Sowerby very shortly after. 



In a letter Dr. Kayser inquires of me if the casts and impressions that occur 

 in the Budleigh-Salterton pebbles are really referable to Sp. Verneuilii, or if they might 

 not belong to a closely allied species to which M. de Verneuil had given the name of 

 Trigeri ; and he notes that in Prance and Germany the true 8p. Verneuilii occurs in the 

 Upper Devonian only. Mr. (Ehlert likewise informs me that Murchison's species has 

 never, with certainty, been found in the Lower Devonian of the West of Prance, and that 

 it seems special to the Upper Devonian of the Boulonnais. 



Having compared a large number of impressions and casts of the Spirifer found at 

 Budleigh-Salterton with a fine series of specimens of Sp. Verneuilii from Perques I am 

 unable to detect any specific difierences whereby to distinguish them, and feel compelled 

 to maintain the opinion I have already published upon the subject. In order to obtain 

 Mr. (Ehlert's opinion I sent him two gutta-percha impressions from specimens taken from 

 the quartzites in question, and without informing him as to their derivation. He answered, 

 " Les deux echantillons dont vous m'envoyez le moulage appartiennent au Spirifera 

 Verneuilii^ et le petit a la variete ArcJdaci" 



As has been already remarked, Spirifera Verneuilii varies considerably in shape ; its 

 small narrow ribs are numerous and simple, with interspaces of about equal breadth. On 

 each valve of a specimen measuring one inch and a half in breadth I have counted 

 seventy-seven ribs, of which seventeen occupied the fold ; and on another example three 

 inches in breadth the number was one hundred. In 1850 M. de Verneuil gave the 

 name Trigeri to a closely allied form, of which the valves were, according to his state- 

 ment, covered with some thirty-six or thirty-seven ribs, of which four or five occupied the 

 fold.^ Thanks to the kindness of Messrs. CEhlert and Guillier I have been able to 

 examine a number of specimens of the Lower-Devonian Sp. Trigeri from different 

 locaUties, and I found that the number of ribs was very variable in different individuals, 

 and that in some specimens they were considerably coarser than in others, and often 

 exceeded the number put down by M. de Verneuil. I was also able to compare these 

 specimens of Sp. Trigeri and Sp. Davousti, de Verneuil,' with a numerous series of 



^ 'Bull. Soc, Geol. de France,' 2nd ser.,vol. vii, p. 781, 1850, also vol. xv, p. 408, 1854 ; ' Appendice 

 a la faune Devonienne du Bosphore,' p. 41, pi. xxi, fig. 1, 1869. 



2 'Bull. Soc. Geol. de France,' 2nd ser., vol. vii, p. 781, 1850; 'Appendice a la faune Devonienne 

 du Bosphore,' p. 43, pi. xxi, fig. 2, 1869, and ' Explication de la Carte Geologique de la France,' par Bayle, 

 vol. iv, pi. XV, figs. 1 and 2, 1873. 



