ANIMALS. 151 



already noticed as occurring at BoUand, induces me to believe that it belongs to the 

 Carboniferous system of this locality. According to Von Buch, it occurs at Meiningen 

 and Schmerbach ; and according to Geinitz, (vide ' Versteinerungen/ Erklarung der 

 Tab. iv) in the under Zechstein and Zechstein-dolomite of Corbusen and Konitz, 

 Germany. The shell which De Verneuil has figured with the name Terehratula elongata 

 (though with a suspicion that it belongs to the present species, of which I have no 

 doubt), is from the Permian marls of Itschalki, near Arzamas, in Russia. From 

 some figures in Miinster's ' Beitrage' (Heft iv, pi. vi, fig. \^ a, b), one would be tempted 

 to conclude that it occurred in the Trias marls of St. Kassian. 



Since my remarks were printed, on " the remarkable valve figured byM. de Verneuil" (vide ante, p. 80), 

 and which I ascertained, before my Synoptical Table in page 81 was printed off", had been elevated to the 

 rank of a genus, under the name of Davidsonia, by M. Bouchard Chantereaux, in a Memoire published in 

 the ' Annales des Sciences Naturelles,' for Aug. 1849, I have been kindly favoured by the author with a 

 copy of the Memoire, in which I perceive that quite a different view is taken of the use of the " cones" from 

 what is advocated by M. de Verneuil and myself. M. Bouchard considers them as adductor muscular 

 impressions ; but, notwithstanding the arguments of my learned friend, I am still in favour of their having 

 been produced by the labial processes. 



From a sketch which Mr. Davidson has just sent me, of the interior of Terehratula pulchella, which 

 belongs to Belthyridaa, I am now satisfied that I was in error in supposing this genus to be without an 

 apophysary system (vide ante, p. 141) ; as the species cited is furnished with a loop agreeing with that of 

 Terehratula. The next question for consideration is — have Ismenia pectunculus and Rhynchora costnta 

 a loop ? 



