BUDLEIGH-SALTERTON PEBBLE-BED. 365 



45. Dinobolus Brimonti, Rouault, sp. Dav., Sil. Mon., PI. I, figs. 21 — 2G (as 



L. Hawkei) ; B. S. Sup., PI. XL, figs. 22, 23. 



Lingula Brimonti, Rouault. Bull. Soc. Geol. de France, 2nd ser., vol. vii, p. 728, 



1850. 1 



— Hawkei, Salter (not of Rouault). Quart. Journ. Geol. Soc, vol. xx, p. 294 



pi. xvii, figs. 2, 3, 1863. 



— Brimonti, Salter. Quart. Journ. Geol. Soc, vol. xx, p. 294, pi. xvii, fig. 6, 



1863. 



— Hawkei, Dav. (not of Rouault). Sil. Mon., p. 41, pi. i, figs. 21— 26, 1866, 



and Quart. Journ. Geol. Soc, vol. xxvi, pi. iv, 

 fig. 3, 1869. 



— Brimonti, de Tromelin. Congres de Nantes, 18/8. 



Dinobolus Brimonti, Dav. Geol. Mag., new ser., vol. vii, p. 340, pi. x, figs. 1 — 6 



1880. 



I never felt satisfied that Salter was correct while referring the specimen under 

 description to the Lingula Hawkei, Rouault, and accordingly, at the time of publishing 

 my Silurian Monograph, I wrote to M. Rouault upon the subject ; but having received 

 no reply to my communication, followed the view taken by Salter, adding, however, 

 " I do not know whether our British specimens answer to the French description." In 

 1879 M. Gaston de Tromelin wrote me that, having been able to induce M. Rouault to 

 show him his collection and types, he was able to assert that the shell Mr. Salter and 

 myself had described and figured as the Lingula Hawkei was, in reality, Rouault's 

 Lingula Brimonti. We were not, however, the only ones to misunderstand Rouault's 

 species, for M. de Tromelin mentions, in his paper above named, that in most collections 

 it bears the name of L. Hawkei. M. de Tromelin states, also, that the specimens from 

 the Loire-Inferieure attain a large size, and that Cailliaud has alluded to the numerous 

 deformations it has been subject to. In a letter he observes that the muscular impres- 

 sions seem to differ so much in this species from those of Lingula or Glottidia that, in 

 his opinion, it should constitute a new genus, a similar view being taken by Professor 

 Bayle. 



Thanks to the liberality of M. Lebesconte, of Rennes, and some other friends, I have 

 been able to study a very extensive series of bivalve specimens also of well-preserved 

 internal casts from Pontrean, in Brittany; and I at once perceived that the species 



1 "Longeur 40 mill.; largeur 46; epaisseur 25 millimetres. Coquille courte, robuste, tres renflee ; 

 la plus 6paisse du genre ; plus large que longue ; tronquee brusquement en avant ; bord parfaitement cir- 

 culaire a partir des angles qu'il forme anterieurement jusqu'a la charniere, de laquelle part, en formant un 

 crochet sur chaque valve, un renflement qui se divise en deux cotes tres marquees qui viennent aboutir aux 

 deux angles que forme le bord en avant. La coquille est en outre couverte sur toute sa surface de lignes 

 d'accroissement tres saillantes. Ne pre'sente avec toutes les especes connues que des rapports generiques. 

 Localite — Guichen, Bain." 



48 



