DAVIDSON — ON SOME FOSSIL BRACHIOPODA. 



469 



'33. Athyeis plano-sulcata, Phillips, Geol. York, vol. ii., pi. x., fig. 15: and 

 -DuY., pi. xri., fig. 2 — 18 and 16 =:ohlonga, Sow. = 

 paradoxa and oltusa, M'Coy. 



34. „ LAiTELLOSA, L'EvelUe, Memoires de la Soc. Geol. de France, 



vol. ii.. p. 11, figs. 21—23 : and Dav., pi. xvi., fig. 1, and 

 pi. xvii., fig. 5 — 6 =. squamosa, Phillips. 



35. „ EXPAXSA, Phillips, Geol. of York, vol. ii., p.'220, pi. x., fig. 18 : 

 , and Dav., pi. xvi., fig. 14, 16, and 18, pi. xvii. fig.l — 5. 



36. RoissYi, L'Eveille, Mem. Soc Geol. de France, vol. ii., pi. ii ,fig. 



18 — 20 = Hmhriata and glabristria. Phillips = dejoressa, 

 M'Coy. 



/ 37. GL0BULAKI3, Phillips, Geol. of York, vol. ii., pi. x , fig. 22. 



I 38. SDBTiLiTA, Hall, in Howard's Ex. of the Valley of the great Salt 



Lake of Uta, pi. ii., fig. 1 : and Dav., pi. 21-22. 

 1 39. „ AiiBiGTJA, Sow., M.C., tab. 376 = sublobata, Portlock =jpentaedra, 

 { Phillips. 



40. Athteis ? GREGARiA, M'Coy, Synopsis, pi. xxii., fig. 18 : and Dav., pi. xv., 



fig. 27 and 28. I have never had the opportunity of 

 studying a perfect example of this shell, and I am even 

 uncertain as to its genus. 



41. Retzia radiaiis, Phillips, Geol, of York, vol. ii., pi. xii. fig. 40 — 41. 



Descriptions and figures of all these species and of their varieties will 

 be found in the portions of my work relating to the Carboniferous 

 Brachiopoda, published in the volume of the Paleeontographical Society 

 for the years 1856, 1857, and 1858 ; but as this Monograph cannot be 

 completed before two or three years, on account of the great number 

 of plates that will be required, the Author will feel greatly indebted 

 towards all those who may feel disposed to assist, by communicating 

 their observations and material. 



EXPLANATION OF PLATE XIL 



1. Spirifera striata, Martin, from which a portion of the shell of the smaller 



valve has been removed, in order to show the back of the spiral 

 cones, and their attachment. 



2. „ Schrenkii, Keyserling. Interior of the smaller or dorsal valve, with 



one of the spiral cones in situ, the other having been removed so 

 as to expose the muscular impressions. A A, adductor, or anterior 

 and posterior occlusor muscle of Hancock. J, Cardinal process, 

 to which was attached Mr. Hancock's divaricator, or cardinal 

 muscle, t, sockets for the reception of the teeth of the opposite 

 valve. 



3. „ Schrenkii, Keyserling. Interior of the larger or ventral valve. D, 



pseudo-deltidium. t, teeth. A, impressions left by the adductor 

 or occlusor muscle. R, of the cardinal or divaricator miiscle. 

 Several instructive fragments of the interior of this species were 

 figured and described by Count A. Von. Keyserling in Dr. Schrenk's 

 Russian work " die Tundren der Samojeden." 



4. „ Cyrt^na, Dalman, interior of the ventral valve. 



5. „ Anossofi, Yerneuil, 



6. „ 3Iosquensis, Fischer, 



These last three figures are here drawn to explain modifications 

 in the shape and development of the diverging dental or rostral 

 plates. 



