T. Davidson — Tertiary Braehiopoda. 463 



var. polymorpha,^ which greatly resembles the Eocene Rhyncho- 

 nella under description, but M. Bayan informs me Dr. Benecke has 

 followed these beds (described by Oppel) into the Tyrol, but did not 

 meet with the Rh. alta, although he mentions T. gerda. These beds 

 would apparently be separated from those containing Massalongo's 

 Rh. polymorpha by the bed with T. diphya, as well as by all the 

 Cretaceous formation, and it is hardly possible to believe that the 

 Bh. alta and Rh. polymorpha could belong to the same species, 

 although some specimens of Oppel's shell may bear some resem- 

 blance to certain Eocene ones. Rh. polymorpha was noticed by Baron 

 de Zigno in 1858. 



Rh. polymorpha was found by Sig. Meneghini at Bolca and Breonio, 

 in the Vicentin, where, according to that able palasontologist, 

 as well as M. Bayan, it may justly be referred to the lowest 

 portion of the Eocene, since it occurs in a bed overlying the Scaglia 

 or Chalk of the Italians. M. Bayan has collected it from his stage 

 A, at Monte Spilecco, near Bolca, and in the Val degli Strangellini, 

 at Novale or the Zovo di Castelvecchio (Zovo being a Venetian patois 

 designation, or corruption of Giogo, jugum). It has also been found 

 by Sig. Meneghini in the Nummulitic beds of Brescia. 



53. Rhynchonella Buchii (Michelotti), PL XX., Fig. 8-13. Rh. 

 Buchii (Michelotti). Brevi cenni d'Alcuni resti delle classi dei 

 Molluschi Acephali e Brachiopodi. Annali delle Scienze del Eegno 

 Lombardo-Veneto, p. 23, 1839, and Faune Miocene de la Haute 

 Italic, p. 77, pi. ii., fig. 25, 1847. Rh. deformis (Seqaenza). Annali 

 degli aspiranti Naturalisti di Napoli. Third series, vol. vi., pi. iii., 

 fig. 3, 3«, 1866. 



In the preceding description we have already referred to this 

 species, which does not appear to quite attain the dimensions of 

 of Rh. polymorpha. Its valves are likewise generally smooth ; short 

 ribs on one half of its valves being of rare occurrence, and I have 

 not yet seen them on both halves of the shell. It was from a 

 crushed example of one of these exceptional specimens (Fig. 13) 

 that Sig. Sequenza formed his Rh. deformis, but which name will, for 

 the reasons above given, require to be placed among the synonyms 

 of Rh. Buchii. According to Michelotti this species would occur in 

 the Lower, Middle, and Upper Miocene. In the Lower Miocene it 

 is found at Chiampo, in the Vicentin, but this stage would, accord- 

 ing to some geologists, form part of the Upper Eocene, and the shell 

 may consequently, perhaps, be a variety of Rh. polymorpha. In the 

 Middle Miocene it abounds at Grangia and Termo Foura, in the hill 

 of Turin, and it is from there that Sig. Eovasenda procured the fine 

 series of specimens figured in my plate. It is found likewise at 

 Sciolze and Callessione, near Turin. In the Upper Miocene at 

 Alta\dlla (Michelotti). 



54. Rhynchonella Meneghiniana (Dav.), PI. XX., Fig. 7. 



Shell small, globular, nearly as wide as long, with about twelve 

 or thirteen ribs on each valve ; beak small, incurved ; valves convex, 



^ Ueber das Vorkommen von jurassichen Posidonomyen-Gesteinen in den Alpen, 

 p. 208, pi. vi., fig. 1. 1863. 



