6 DE. T. DAVIDSON ON EECENT BEACHIOPODA. 



As there are certainly some differences observable in the two groups, and as none of 

 the recent species would agree in the characters of their loops and in certain other 

 particulars with the forms referred to the genus Terebratula of Llhwyd and Klein, it 

 may perhaps be better to adopt Douville's generic name Liothyris for the species we are 

 about to describe. 



In the larger number of the recent species, sucli as in Liothyris vitrea, L. arctica, 

 L. Moseleyi, L. tiva, L. Bartletti, L. WyvilUi, and L. suhqnadruta, the connecting band of 

 the loop is narrow, while in L. splicBnoidea—cubensis it is larger. 



The specific claims of Liothyris cernica, and L.? DalU are still uncertain, only a single 

 example of each of them having been hitherto discovered. 



Very small, or scarcely any modifications in the shape of the loop have been observed ; 

 all the species have their shell minutely perforated l)y canals, and calcareous spicules are 

 abundant in the mantle. 



1. Liothyris vitrea, Born, sp. (Plate I. figs. 1-12.) 



Anomia vitrea, Bora, Testacea Musei Caes. p. 119, vignette, 1778; Linn^, ed. Gmelin, p. 3347, 

 1788. 



Gnjphus vitrea, Megerle v. Miihlfeld, Berliu Mus. 1811. 



Terebratula vitrea, Lamarck, An. sans Vert. vol. vii. p. 245, 1819; Payraudeau, Cat. p. 83, no. 160, 

 1826; G. Bronn, Italicus Tertiar-Gebilde, p. 125, 1831; Pliilippi, Enum. Moll. Sicilise, vol. i. p. 95, 

 t. 6. figs. 6-8, 1836, vol. ii. p. 66, 1844; A. Scacclii, Cat. Couch. Regni Neapolitaui, p. 8, 1836; 

 Kiister, Martini & Chemnitz, Conch. -Cab. vol. vii. p. 22, tab. 2. figs. 11-13, 1843; E. Forbes, Report 

 on the Mollusca of the Mgenn Sea, Brit. Assoc. Report, p. 141, 1843; D. Galvani, Illustrazione 

 delle Conch. Foss. 1845 ; G. B. Sowerby, Thes. Conch, vol. i. p. 353, pi. 70. figs. 56-59, 1846 ; Aradas 

 (pars) Conchiglie fossili di Gravatelli, p. 14, 1851 ; O. G. Costa, Fauna del regno di Napoli, p. 33, 

 pi. i. figs. 1-3, 1851-52; Davidson, Sketch of a Class, of recent Brachiopoda, Ann. & Mag. Nat. Hist, 

 vol. ix. p. 364, 1852, and Br. Foss. Brach. Pal. Soc. vol. i.. Introduction, p. 62, fig. 23, and pi. vi. 1852; 

 S. P. Woodward, Manual of Mollusca, p. 215, 1856; L. Reeve, Conch. Icon. pi. 3. fig. 8, 1860, and 

 Journ. de Conch, vol. ix. p. 124, 1861 ; Chenu, Man. de Couch, vol. ii. p. 201, 1862 ; Segucnza, Atti 

 della Soc. Italiana di Scienze Nat. vol. i. p. 17, pi. 1. figs. 1-7, 1865; H. C. Weiukauft', Die Conch. 

 Mittelmeeres, vol. i. p. 284, 1867 ; Davidson, Italian Tert. Brach., Ann. & Mag. Nat. Hist. vol. vii. 

 pi. xvii. fig. 11, 1870; Jeflreys, Ann. & Mag. Nat. Hist. 5th ser. vol. x. p. 28, 1882. 



Liothyris vitrea, Douville, Bull. Soc. Geol. de France, 3'' ser. vol. vii. 1879 ; E. Deslongchamps, Note 

 sur la Classification des Terebratules, ou Etudes critiques sur les Brachiopodes, pp. 106 & 153, pi. xx. 

 figs. 7-11, 1884. 



Shell longitudinally oval or ovate, globose, widest about the middle, laterally rounded 

 or more or less pinched in near the front, front margin nearly straight or gently 

 rounded. Colour nearly white, surface smooth, semitransparent, glassy, marked with 

 fine concentric lines of growth and perforated by minute canals. Dorsal valve tumidly 

 convex, longitudinally flattened along the middle, from which the anterior lateral portions 

 slope to the edge. Venti-al valve slightly deeper than the dorsal one, longitudinally 

 flattened along the middle ; beak incurved, moderately produced and slightly overlying 

 the umbo of tlie dorsal valve, obliquely truncated l)y a very small circular foramen 

 with thickened margin and separated from the hinge-line by a small triangular deltidium 

 in two pieces. Loop in the interior of the dorsal valve simple and short, attached by its 



