mi. T. DAVIDSON ON EECENT BRACHIOPODA. 9 



fig. 707, 1785, cannot surely belong to Bern's species, for he figures in it a longitudinal 

 septum, Avhich never occurs in that species. 



Several varieties of Z. v'ltrea have received distinctive names. 



LiOTHYRis viTREA, var. MINOR, Philippi. (Plate I. fig. 13.) 



Terebratula ritrea, var. minor, Tliilippi, Enuracratio Moll. Siciliffi, vol. i. p. 99, pi. vi. fig. 8, 183G ; vol. ii. 

 p. (](), 1814.. 



Terebratula affinis, Calcara, Ceimo sui Mollusclii viventi c fossili di Sicilia, p. 48, 1845. 



Terebratula vitrea (pars), A. Aradas, Descrizione dclle concliiglie fossili di Gravatelli presso INIessiua, 

 p. 14, 1847. 



Terebratula minor, E. Suess, Ueber die Wohnsitze der Brachiopoden, 1859; Davidson, On recent 

 Terebratula;, Ann. & ]Mag. Nat. Hist. 3rd ser. vol. viii. p. 35, 18fil. 



Terebratula affinis, G. Seguenza, Notizie succinte intorno etc. pp. 19, 2G, 32, 1862 ; id. Sulla 

 formazionc mioc. di Sicilia etc. p. 7, 1862. 



Terebratula minor, Davidson, Outline of the Geology of the Maltese Islands by Dr. Leith Adams ; 

 and Description of the Brachiopoda by Thos. Davidson, Ann. & Mag. Nat. Hist. 3rd ser. vol. xiv. 

 p. 8, pi. i. fig. 8, 1864; Seguenza, Memorie della See. Ital. di Scieuze Naturali, vol. i. p. 21, 1865; 

 Kowalevsky, Observations on the Development of the Brachiopoda (in Russian). Nachr. Ges. Mosc. xiv. 

 1873. 



Shell small, ovate, longitudinally oval, longer than wide, about 9 lines in length by G 

 in breadth and 5i in depth. Valves uniformly convex and smooth, no fold or sinus ; 

 ventral valve somewhat deeper than the dorsal one ; beak moderately incurved, and 

 truncated by a small circular foramen slightly separated from the hinge-line by a narrow 

 deltidium in two pieces ; loops short and simj)le. Colour pale yellowish white. 



Hah. Living in the Straits of Messina and off the Eolio Islands in the Mediterranean; 

 off Cape of St. Vincent (' Talisman ' Expedition), in 298-818 fathoms. 



Ohs. Considerable uncertainty has prevailed with respect to this small shell, which 

 Philippi, in 1836, described from fossil Pliocene specimens as a variety of Terebratula vitrea. 

 Suess and otlaers declare it to be a distinct species, while others look upon it as a young 

 stage of Liothyris vitrea. I have compared species of the fossil shell with species dredged 

 alive by Prof. Seguenza in the bay of Messina, and found them to be identical. I cannot, 

 however, get rid of the idea that Liothyris minor is more than a small race or variety 

 of Liothyris vitrea ; it occurs, associated with the last-named shell, in the same beds and 

 localities in Calabria and in Sicily. 



To Kowalcvsky's memoir on the development of the Brachiopoda (1873) the reader is 

 referred for observations relative to the embryology of L. minor. 



Liothyris vitrea, var. Davidsoni, A. Adams. (Plate I. figs. 14-16.) 



Terebratula davidsoni, A. Adams, Proc. Zool. Soc. London, p. 314, 1867. 

 Terebratula minor, Davidson, Proc. Zool. Soc. London, p. 302, pi. xxx. fig. 10, 1871. 



Shell ovate, broadest anteriorly, tapering posteriorly, longer than wide, marginally 

 rounded. Valves uniformly convex, no fold or sinus, surface smooth, with faintly marked 

 concentric lines of growth ; beak incurved, truncated by a small circular foramen 

 margined laterally by two small deltidial plates ; surface of shell finely punctured. 



second series. — zoology, vol. IV. 2 



