116 DK. T. DAVIDSON ON RECENT BEACHIOPODA. 



Terehratula rosea, G. B. Sowcrby, Cat. of Shells of the late Earl of Tankerville, p. 28, 1825. 



Terehratula tulipa, Blaiuville, Diet. So. Nat. liii. p. 144, 1828. 



Terehratula rosea, Sander Rang, Manuel de THistoire naturelle des Mollusques, pi. 8. figs. 1-3, 

 18.29; Deshayes, ed. Lamarek, An. sans Vert. vol. vii. p. 350, 1836. 



Terehratula unguis, Kiister, ed. Martini & Chemnitz, Conch. -Cab. p. 35, pi. 2 b. figs. 8-10, 1843. 



Terehratula rosea, d'Orbigny, Voyage dans I'Amerique Meridionale, vol. v. p. G74, 1847. 



Bouchardia rosea, Davidson, Bull. Soc. Geol. de France, 2" sir. vol. vii. p. 62, pi. i. figs. 1-6, 1849 ; 

 Classification of Recent Brachiopoda, Ann. & Mag. Nat. Hist. 2nd ser. vol. ix. p. 372, 1852. 



Pachyrhynchus roseus. King, A Monograph of English Permian Fossils, Pal. Soc. p. 70, 1850. 



Bouchardia tulipa, Woodward & Gray, Catalogue of the Brach. in the Brit. Mus. p. 100, 1853; 

 S. W^oodward, A Manual of the MoUusca, p. 218, 1856. 



Terehratula rosea, Hanley, Recent Shells, p. 322, 1856. 



Terehratula (Bouchardia) tulipa, L. Reeve, Conch. Icon. pi. mi. fig. 33, 1861. 



Bouchardia tulipa, Adams, The Genei'a of Recent Mollusca, vol. ii. p. 577, 1858 ; E. Sucss, Ueber 

 die W^ohnsitze der Brachiopoden, Sitzungsb. k. Akad. der Wissensch. W^ien, Bd. xxxvii. p. 210, 1859; 

 Dall, Eevision of the Terebratulidse, Amer. Journ. of Conch, vol. vi. p. 141, 1870. 



Bouchardia rosea, Dall, Proc. Acad. Nat. vSci. Philadelphia, 1873, p. 191. 



Shell thick, with a nearly straight heak, longitudinally oval or spindle-shaped, longer 

 than wide ; surface smooth, marked here and there with concentric lines of growth. 

 Colour yellowish red, pink throughout or sparingly rayed with bright crimson. Length 

 9 lines, breadth 5i liaes, depth 4 lines. Dorsal valve very gently and uniformly convex 

 posteriorly, anteriorly more or less depressed along the middle. Ventral valve slightly 

 deeper than the dorsal one, longitudinally keeled ; beak triangularly acuminated, almost 

 erect, very little incurved, and truncated by a small terminal circular foramen widely 

 separated from the hinge-line by a concave false area, with two narrow grooves along the 

 middle ; deltidium blended with the shell. Interior of the valves much thickened 

 posteriorly. The interior of the dorsal valve is unusually thickened posteriorly, to about 

 one third of its length ; hinge-plate large and solid, provided with V-shaped diverging 

 grooved ridges, and much elevated above the other portions of the shell, especially 

 anteriorly. These long scooped-out ridges probably served for the attachment of the 

 cardinal muscles. On each side, on a lower level, are the lateral portions of the hinge- 

 plate, and close to the hinge-line on each side the dental sockets. No cavity exists under 

 the hinge-plate, which is massive ; but from its sunken base a mesial septum of about one 

 third the length of the valve extends, this gradually rises until it becomes abruptly 

 elevated anteriorly in the shape of a wide perj^endicular plate, and to the posterior laljial 

 slopes of which are fixed anchor-shaped disconnected curved lamellae, broad at their 

 attachment to the sides of the septum and gradually tapering to a point At the bottom 

 of the valve on each side of the septum are faintly impressed muscular scars. In the 

 interior of the ventral valve the shell is much thickened at and near to the beak, as well 

 as longitudinally ; along its centre extends a wide sliglitly raised ridge with two oval- 

 shaped muscular impressions on each side ; two deviating massive ridges, deeply excavated 

 along the middle, extend from under the beak to about one third of the posterior length 

 of the valve. Teeth for the interlocking of valves strong. The positions of the occlusorj 



