18 DE. T. DAVIDSON ON RECENT BEACHIOPODA. 



Terebratula costata, Lowe, Zool. Journal, vol. ii. p. IOj, 1825. 



Terebratula emarginala, Risso, Hist. Nat. de rEurope Meridionale, vol. iv. p. 388, pi. xii. fig. 175, 182G. 



Terebratula quadrata, Risso, ibid. p. 389, pi. iv. fig. 176, 1826. 



Delthyris spatula, Menke, Synopsis Methodica MoUuscorum, 2nd ed. p. 96, 1828-30. 



Terebratula caput-serpentis, Philippi, Enum. Moll. Siciliie, vol. i. p. 84, tab. vi. fig. 5, 1836; Anton, 

 Verzeichniss der Concliylien, p. 23, 1836. 



Terebratula Gervillei, S. V. Wood, Ann. & Mag. Nat. Hist. 1st ser. vol. vi. p. 253, 1840. 



Terebratula Chemnitsii, Kiister, Martini & Chemnitz, Concliylien-Cabinet, vol. vii. p. 37, pi. 2i. 

 figs. 19 and 20, 1843. 



Terebratula caput-serpentis, G. B. Sowerby,Thes. Conch, vol. i.p. 343, pi. ixviii. figs. 1-4, and pi. Ixxii. 

 fig. 116, 1846. 



Terebratulina caput-serpentis, d'Orbigny, Ann. des Sci. Nat. vol. viii. p. 67, pi. vii. figs. 7 & 8, 1848. 



Terebratulina cornea, d'Orbigny, 1848. 



Terebratula caput-serpentis, Forbes and Hanley, Brit. Moll. pi. ivi. figs. 1-4, 1849. 



Terebratulina caput-serpentis, Davidson, Sketch of a Classification of Recent Brachiopoda, Ann. & 

 Mag. Nat. Hist. 2nd ser. vol. ix. p. 365, 1852; Davidson, Br. Tert. Brach., Pal. Soc. vol. i. p. 12, pi. i. 

 figs. 3-6,1852. 



Terebratula striata. Leach, Br. Moll. 1852. 



Terebratulina striata, S. P. Woodward, Manual of the Mollusca, p. 215, 1854; Hancock, Phil. 

 Trans, vol. cxlviii., 1858. 



Terebratula striata, L. Reeve, Conch. Icon. pi. iv. fig. 15, 1860. 



Terebratulina striata, E. Deslongchamps, Recherches sur TOrganisation du Manteau chez les Brachio- 

 podes articules, 1864; Brusina, Moll. Dalmati, Verh. zool.-bot. Ges, Wien, Bd. xvi., 1866; Dall, Proc. 

 Acad. Nat. Sciences of Philadelphia, p. 179, 1873 ; Kowalevsky, On the Development of the Brach., 1874 ; 

 G. O. Sars, Bidrag til Kundskaben om Norges Arktiske Fauna, Mollusca Regionis Arcticae Norvcgiae, 

 tab. i. fig. 5, 1878 ; Jeffreys, Brit. Conch, vol. ii. p. 14, and vol. v. pi. xix. fig. 2, 1873-79 ; E. Deslong- 

 champs, Etudes critiques sur des Brachiopodes nouveaux ou peu connus, 1884*. 



Shell ovate, somewhat pentagonal, longer than wide, broadest about the middle, 

 slightly rounded or indented anteriorly ; dorsal valve more or less uniformly convex, 

 but with sometimes a mesial longitudinal depression, marginally flexuous on the sides ; 

 lateral sides of the umbo auricular ; ventral valve convex, rather deeper than the dorsal 

 one, anteriorly mesially depressed ; beak rather short, gently incurved and obliquely 

 truncated by an incomplete foramen, posteriorly margined by the substance of the beak, 

 anteriorly by the extremity of the umbo, laterally by two small deltidial plates, no 

 distinct cardinal area or beak-ridges ; surface of shell densely covered with fine radiating 

 striae, few in number, coarse and simple when young, but rapidly increasing in 

 number with age, by means of bifurcation, and by the interpolation of smaller and 

 shorter ribs; both valves are also crossed by numerous concentric raised lines of 

 groAvth, more prominent in the young, finer and closer as the shell increases in size. 

 Loop short and simple in the young, with age becoming annular through the union 

 of the oral processes. Colour whitish, with a tinge of yellow, sometimes rust-stained. 

 Dimensions variable ; a large example measured 1 inch 3 lines, breadth 1 inch, depth 

 \ inch. 



* In addition to the above references, the species has been aUudcd to by many other eonchologists and palieonto- 

 logists, such as by Gualtieri, in his Index Conch, tab. 96. fig. 3, 1742 ; by Davila, Cat. i. pL xx. ; Favanno, Conch, 

 pi. 41. fig. A", 1780, and by many others. 



