17(i DE. T. DAVIDSON OX EECENT BEACHIOPODA. 



DESCRIPTION OF THE PLATES. 

 Plate XIII. 



Figs. 3-9 a. Terebratella coreanica, Adams aud Reeve, sp. 3. Type specimen figured by Reeve. 4-4 c. A 

 fine aud large specimen. 5, 5 a. A still larger example {Terebratula miniata, Gould), drudged 

 by L. V. Schrenk, from Hakodadi, Japan. 6, (Sa. An elongate globose variety, dredged by Capt. 

 St. John in Tsuga Strait. 7. Interior of dorsal valve, to show loop. 8, 8 a. Elongate variety 

 [T. Botic/uadi, Dayldson). 9,9a. Var. 5r;McAarrfi, Davidson. Specimens 4, 5, 6, 7, and 8, in 

 the Davidson Collection, Geol. Dept., British Museum ; 9, in the Zool. Dcpt., British 

 Museum. 



Plate XIV. 



Figs. 1-8. Terebratella cruenta, Dillwyn, sp., of different forms and ages; from Cook's and Faveau Straits, 

 New Zealand. All in the Davidson Collection, Geol. Dcpt., British Museum. \,la,\b. Avery 

 large and fine example. 2. An elongated form. 4. Interior of dorsal valve, showing the loop. 



8. A young specimen, showing a modification in the loop. Another modification is represented 

 in figs. 5 ff, 5 6, which was described under the name of Terebratella Evansii, but it is really a 

 young form of Terebratella cruenta. 



Figs. 9-19. Terebratella dorsata, Gmelin, sp. Different forms and ages ; chiefl}' from Magellan Straits. 



9, 9 a, 9 6. A large specimen {T. magellanica, Chemnitz). Figs. 11, 11 «. Terebratella chilensis, 

 Brodcrip. 14. Represents the Terebratella Soireibyi, King. 17. Full-grown condition of 

 the loop. 18, 19. Young form, showing one of the early stages of the development of the loop. 



Figs. 20-21a. Terebratella lupinus, Philippi, sp. Probably a young stage of Terebratella dorsata, with 

 Ma^ase//a-shaped loop. Magellan Straits; type in Berlin Museum (no. 7979). 



Plate XV. 



Figs. 1-8 «. Terebratella frontalis, Middendorff, sp. 1-2 6. Dredged by W. Dall at Atka Island ofi" the 

 Aleutian Chain, Alaska ; 2. A large example. 3, 4, 5, .T «. Dredged by Capt. St. John, off East 

 Yeso, North Japan. G. Interior of the dorsal valve to show the loop. 7. Interior of same 

 valve, with the loop removed to show the occlusor muscular scars. All in the Davidson 

 Collection, Geol. Dcpt., British Museum. 8, 8 «. Shell-structure after Middendorff. 



Figs. 9-12. Terebratella Blanfordi, Dunker, sp. 9 and 11. Types after Duuker, from Wakayama, 

 Japan. 10. A specimen from the same locality (Davidson Collection, Geol. Dept., British 

 Museum). 12. Interior of the dorsal valve to show the loop. 



Figs. 13-14. Terebratella Maria, A. Adams. Dredged by A. Adams at Satanomosaki, Japan. 

 13. Natural size. 14. Interior seen in profile to show the loop (Davidson Collection, Geol. 

 Dept., British Museum). 



Figs. 15-29. Terebratella rubicunda, Sowerby. Faveau and Cook's Straits, New Zealand. 15—24. A 

 variety of forms and ages in the Davidson Collection, Geol. Dept., British Museum, 22, 23. 

 Modifications of the loop. 24. Adult condition of loop. 25. Vertical section of the ventral 

 valve near the extremity, considerably enlarged, so as to show the ordinary trumpet-like form 

 of the vertical passages, and the remarkable contraction which they exhibit in the inner aud 

 (probably) later formed layer; magnified 100 diameters (after Carpenter). 26. Another portion 

 considerably enlarged, showing the occasional bifurcation of the vertical passages ; magnified 

 100 diameters (after Carpenter). 27 a, 27 b. Young T. inconspicua, Sowerby, from his figures 

 in the Thes. Conch, pi. xxxi. figs. 102, 103, 104. 28, 29. Terebratella rubicunda, Sowerby, sp. ; 

 young elongated form from Chatham Islands, S. of New Zealand. 



