BRACHIOPODA. 229 



Order Protremata 



Superfamily Orthacea 



Family Orthidae 



Genus Dalmanella Hall and Clarke 



Dalmanella lenticularis (Vanuxem) 



Plate 61, figures 9-11 



1867. Orlhis lenticularis Vanuxem, (non Wahlenberg), Geol. N. Y., Rept. Third Dist., 



1842, p. 139, fig. 4. Hall, Nat. Hist. N. Y. Pal., 4, 1867, p. 35, pi. 5, figs. 1, 2. 



1843. Orthis lenticularis and 0. lentiformis Hall, Geol. New York, Rept. Fourth Dist., 



p. 17, fig. 4. 

 1889. Orthis eboracensis Miller, N. Amer. Geol. Pal., p. 357. 

 1892. Dalmanella lenticularis Hall and Clarke, Nat. Hist. N. Y. Pal., vol. 8, pt. 1, 



pp. 207, 224, pi. 5c, figs. 36-41. 



Description— Shell of medium size, sub-elliptical to sub-ovate in outline, plano- 

 convex, width greater than length or almost equal, the greatest width near the middle 

 of the shell. The dimensions of a large pedicle valve are: Length 17 mm., width 19 

 mm. A small brachial valve measures 12 mm. in length, and 12.5 mm. in width. Cardi- 

 nal extremities rounded. 



Pedicle valve highly convex, the greatest convexity at or a little anterior to the 

 umbonal region. Shell surface sloping gently to the lateral and anterior margins; beak 

 small, blunt, incurved over the hinge line. Character of foramen not observed. A 

 cast of the interior shows the long, narrow median septum extending from the beak 

 almost to the anterior margin. 



Brachial valve from depressed convex in the upper part to almost flat at the lateral 

 margins; median portion marked by an ill-defined sinus which broadens out at the an- 

 terior margin forming a wide shallow depression Beak small, projecting slightly beyond 

 the hinge line. 



Surface of both valves marked by fine, radiating, bifurcating costae of uniform size, 

 the bifurcations as many as four in passing from beak to anterior margin ; 5 costae occupy 

 the space of 1 mm. Coarser imbricating concentric growth lines cross the striae. 



Remarks — This characteristic Onondagan species is represented here by the sepa- 

 rate valves only. In the essential features the specimens observed agree closely with 

 those figured by Hall in the New York reports, with this exception, that in the Little 

 Saline forms the costae maintain a more uniform size. 



Horizon — Upper beds. 



Figured specimens No. 27481 Walker Museum. 



Dalmanella oriskania sp. nov. 

 Plate 61, figures 12-14 



Description — Shell of medium size, length usually slightly greater than width, al- 

 though a number of the specimens have the length and width practically the same. 

 The type specimen, a pedicle valve, measures 20 mm. in length and 19 mm. in width. 

 The shape varies from semi-elliptical to semi-circular. 



Pedicle valve highly convex, elevated or carinated along the median line, the 

 greatest elevation at the umbonal region. The surface of the shell slopes rather steeply 

 to the lateral and cardinal margins, but more gradually towards the anterior margin. 

 Cardinal margins meet the beak at an obtuse angle, extremities rounded. Beak small 

 and slightly incurved over the hinge line. 



