BRACHIOPODA. 73 



formed. The figures of Merista prunulum, Schnur, from the Eifel, given by 

 QuENSTEDT,* indicate that the same feature is also present in this species. It 

 will be conceded that the taxonomic value of this feature is as important as 

 the present basis of distinction between Merista and Meristella, and it is very 

 probable that these Devonian species will afford differences in the structure of 

 the loop.f It will doubtless serve a useful purpose to separate such Devonian 

 species from typical Merista, and the nanie Dicamara is therefore proposed. 



Genus MERISTELLA, Hall. 1859. 



I'LATKS XLIV, XLV. 



1842. Atrypa, Conrad." .Journal Acad. Nat. Sci. Philailelphia, vol. viii, p. 26.^. 



1842. Atrypa, Vanuxbm. Geology of N. Y. ; Kept. Third Di.st.. p. 120, tig:. 2. 



1843. Terebi-atula, Castelnau. Essai siir le Sjsteme Silurien de rAmer. Septeii., p. 39, pi. xiii, fig-. 6. 

 1843. Atrypa, Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 202, fig. 2. 



1857. Merista, Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. 92, figs. 1-7 ; p. 94, figs. l-« ; p. 95, 



figs. 1-4 ; p. 97. 



1858. Atrypa, Rogers. Geology of Pennsylvania, vol. ii, part ii, p. 825, fig. G42. 



1859. Merista, Hall. Palseontology of N. Y., vol. iii, pp. 247-252, 431, pis. xxxix, xl, xli, xliv, ci, 



fig. 3. 



1860. Meristella, Hall. Thirteenth Rei>t. N. Y. State Cab. Nat. Hist., pp. 74, 84, 93, tigs. 5-9; p. 95, 



tigs. 1-5. 

 1860. ^Mv/ri.? .', Billings. Canadian Journal, [vol. v, new ser., p. 279, p. 274, tigs. 29-32; p. 281, 



tigs. 43, 44. 

 1S61. Meristella, Hall. Fourteenth Kept. N. Y. Slate Cab. Nat. Hist., p. 100. 



1862. Meristella, Hall. Fifteenth Rept N.Y. State Cab. Nat. Hist., p. ItiO, figs. 17-22, pi. iii, figs. 21, 22. 



1863. Meristella, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., p. 50, figs. 27-34. 

 1863. Meristella, Hall. Amei-iean Journal of Science, vol. xxxv, p. 396; vol. xxxvi, p. 11. 

 1863. Meristella, Hall. Transactions of the Albany Institute, vol. iv, pp. 139, 140. 



1863. Atliyris, Billings. Pj-oc. Portlan<l Soc. Nat. Hist., vol. i, pp. 115, 116, pi. iii, tigs. 13, 14. 



1863. Charionella, Billings. Geology of Canada, p. 373, fig. 397; p. 374, figs. 400«, 401; p. 3S5, tig. 420. 



18B6. Merista,' A. Winchell. Geol. Rept. of the Lower Peninsula of Michigan, p. 94. 



1867. Meristella, Hall. Paleontology of N. Y., vol. iv, pp. 295-299, 303-308, 420, plates xlviii, xlix, 1, 



figs. 1-17; Ixiii, figs. 15-22. 



1868. Merista, Meek and Wortuen. Geological Survey of Illinois, vol. iii, p. 376, pi. vii, tig. 8. 

 1874. Athyris, Nicholson. Palfeonfology of the Province of Ontario, p. 86. 



1874. Athyris, Billings. Canadian Naturalist and Geologist, vol. vii, new ser., p. 240. 



1884. Meristella { Whitfieldia), Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 148, i)l. iii, fig. 8. 



1889. Meristella, Nettblrotu. Kentucky Fossil Shells, pp. 97, 98, pi. xv, tigs. 2-8. 



1889. Merintella, Simpson. Transactions of the American Philosophical Society, vol. xvi, p. 442, tig. 7. 



* Petrefactenkunde Deutschlands ; Brachiopoden, pi. Ii, tigs. 69-75. 1871. 



t Dr. Davidson refers to jireparations of Merista prunulum by Zogmayer, and implies that there are 

 some minor dift'ei-ences in the loop, etc., from these structui-es in M. Jieratlea. Dr. Zugmayer's observations 

 have not been published, and therefore we can venture no opinion as to how fai- such ditferences as he may 

 have discovered will fortify the distinction above indicated between the Silurian and Devonian species cur- 

 rently referred to Merista. 



