PALEONTOLOGY OF NEW YORK. 
had given excellent figures, showing very completely the characters of the 
pedicle-valves of O. desquamata (= 0. crassa, Hall), and 0. gemma, Billings. 
But in 1863,^ the interiors of both valves of Obolella? polita, Hall, had been 
illustrated, and the figure given of the pedicle-valve (there termed “ dorsal ? ”) 
represents the impressions almost precisely as we now know them to be in the 
corresponding valve of 0. chromatica, 0. crassa, and others; while those of the 
opposite valve, usually less distinctly retained than in the pedicle-valve, show 
the long, curved laterals and the central scar. (See further under discussion 
of Dicellomus.) In 1881, Mr. FoRDf demonstrated the interior characters of 
the brachial valve of 0 . crassa, subsequently amplifying his observations some¬ 
what in a figure published by Mr. Walcott in Bulletin No. 30, 1886. In this 
work, Mr. Walcott also gives a figure of the interior of the same valve of 
0. chromatica, demonstrating the complete harmony of its scars, both in 
arrangement and development, with those of 0. crassa. The same author 
gives, in addition, illustrations of the interiors of 0. gemma, and 0. Circe, 
Billings. 
The genus Obolella possesses, as far as known, a larger specific representation 
than any other group of primordial brachiopods, but all species that have been 
referred to the group are not congeneric. The true Obolella, as far as it is 
accurately known, is not only confined to primordial faunas, but is believed to 
be largely American in its representation. The forms referred by English 
writers to the genus fail to show the characteristic generic features. Some 
of them have already been assigned to other genera, e. g., 0. sagittalis, Salter, 
to Linnarssonia, Walcott, to which genus probably belong 0. Belti, Davidson, 
and 0. maculata, Hicks; 0. Sabrina, Callaway, will undoubtedly prove a repre¬ 
sentative of a distinct genus, its relations to Acrotreta having been pointed out 
by Mr. Walcott. 
Certain of M. Barrande’s species show internal features indicating their 
close alliance to Obolella, e. g., Lingula Feistmanteli,% Obolus? complexus ,§ Obolus 
* Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist. .( loe . cit.). 
f American Journal of Science, vol. xxi, p. 131. 
J Syst. Sil. Boheme, vol. v, pi. 106, fig. iv. 
§ Syst. Sil. Boheme, pi. 95, fig. iii; pi. Ill, fig. vi; pi. 152, fig. ii, 4. 
