BRACHIOPODA. 
97 
Genus IP HIDE A, Billings. 1872. 
PLATE IV, FIGS. 0-9. 
1872. Iphidea, Billings. Canadian Naturalist, New Series, vol. vi, p. 477. 
1874. Iphidea, Billings. Palaeozoic Fossils, vol. ii, pt. i, p. 76. 
1876. Iphidea, Linnarsson. Brachiopoda of the Paradoxides Beds of Sweden, p. 25. 
18S6. Iphidea, Walcott. Bulletin No. 30, U. S. Geological Survey, p. 100. 
Diagnosis. “ Of this genus we have no specimens showing the internal 
structure, but the external characters seem sufficient to separate it from any 
described generic group. The ventral ? valve of I. bella is conical, strongly 
elevated at the beak, hinge-line nearly straight, posterior angles narrowly 
rounded, sides and front nearly uniformly rounded, forming rather more than 
a semicircle. Posterior side with a large false area and a convex pseudo-delt- 
idium, the width of which at the hinge-line is nearly one-third the whole 
width of the shell. The dorsal valve is semicircular, moderately convex, most 
elevated at the beak The hinge-line appears to be straight. * * * § * * 
The surface is covered with fine concentric striae, which in the ventral valve 
are continued around on the area.”* 
Type, Iphidea bella. 
The foregoing diagnosis is derived from the original description of the type- 
species, Iphidea bella. After the lapse of eighteen years since the date of its 
publication little has been contributed to our knowledge and no facts of 
essential importance bearing upon the external characters of these shells; 
of the interior we still know nothing. In 1873, Mr. Meek described the species 
Iphidea {??) sculptilis,\ from the Gallatin River, Montana, but as the hinge-line 
and subapical area of the shell have not been observed, and on account of its 
apparent specific identity with the Kutorgina minutissima, Hall and Whitfield, it 
has been referred provisionally to the genus Kutorgina by Mr. Walcott, and 
the latter species reduced to a synonym4 Dr. Linnarsson described the species 
I. ornatella, from the Paradoxides beds,§ giving good figures of the exterior of 
* Billings. Canadian Naturalist, 1872, loc. cit. 
•f Preliminary Palaeontol. Rept. : Sixth Ann. Rept. U. S. Geological.Survey Terr., p. 479. 
t Palaeontology Eureka District, p. 20. 
§ Brachiopoda of the Paradoxides Beds of Sweden : Bihang till K. Svenska Vet Akad. handiingar, Bnd. 
3, No. 12, p. 25, pi. iii, tigs. 42, 43. 
