PLATE IV. 
Micromitra (I[PHIDELLA) PANNULA (White) (p. 361). 
[Text fig. 32, p. 362, and P1. IV, figs. 3 and 3a.]} 
Fiaures 1 and la. Apical and side views of a ventral valve from Locality 74, Middle Cambrian ‘‘Tonto” sandstone 
Grand Canyon of the Colorado, Arizona. U.S. Nat. Mus. Cat. No. 51446a. 
lb. Dorsal valve from Locality 149a, Middle Cambrian limestone on Pole Creek, Madison County, Montana. 
U.S. Nat. Mus. Cat. No. 51445b. 
lc. Dorsal valve from Locality 14, Middle Cambrian limestone 7 miles southwest of Rome, Floyd County, 
Georgia. U.S. Nat. Mus. Cat. No. 51444c. 
id and le. Posterior and side views of ventral valve from Locality 30, Lower Cambrian limestones near 
Pioche, Nevada. U.S. Nat. Mus. Cat. No. 51452a. Copied from Walcott [1908c, Pl. I, figs. 1b 
and la, respectively.] The figures were there wrongly placed as the posterior and side views of the 
specimen represented by figure Ir of this plate. The latter specimen occurs in British Columbia; 
the one represented by figures 1d and le occurs in Nevada. 
lf. Posterior view of the dorsal valve represented in figure 1b, showing the characters described in the text 
(see p. 362). U.S. Nat. Mus. Cat. No. 51445b. 
lg. Drawing of the type specimen of the species. Locality 31a, Lower Cambrian siliceous shale near Pioche, 
Nevada. U.S. Nat. Mus. Cat. No. 1533la. Specimen figured by White [1877, Pl. I, figs. 4a and 4b] 
as Trematis pannula; and by Walcott [1886b, Pl. VII, figs. 3 and 3a; and 189la, Pl. LXIX, fig. 5d] as 
Kutorgina pannula. The surface is enlarged in figure 1o of this plate. 
1h and li. Apical and posterior views of a dorsal (?) valve from Locality 78a, Middle Cambrian “‘Tonto” 
‘sandstone, Grand Canyon of the Colorado, Arizona. U.S. Nat. Mus. Cat. No. 51447a. The surface 
is enlarged in figure In of this plate. i 
Jj and 11. Apical and side views of a small specimen from Locality 31a, Lower Cambrian limestone near 
Pioche, Nevada. U.S. Nat. Mus. Cat. No. 15333a. Specimen figured by Walcott [1886b, Pl. VIII, 
figs. 2 and 2a; 1891a, Pl. LXIX, figs. 5 and 5a] as Kutorgina pannula. 
1k. Dorsal valve from same locality as the specimens represented by figures 1j and 11. U.S. Nat. Mus. 
Cat. No. 15333b. Specimen figured by Walcott [1886b, Pl. VIII, figs. 2b and 2c; 1887, Pl. I, fig. 14b; 
and 189la, Pl. LXIX, figs. 5b and 5e] as Kutorgina pannula. The outer surface is enlarged in figure 
Ip of this plate. 
Im. Ventral valve from Locality 38a, Lower Cambrian limestones near North Granville, Washington County, 
New York. U.S. Nat. Mus. Cat. No. 17442a. Specimen figured by Walcott [1887, Pl. I, figs. 14 and 
14a; and 1891a, Pl. LXIX, figs. 5¢ and 5f] as Kutorgina pannula. The outer surface is enlarged in 
figure 1q of this plate. 
In. Enlargement of a portion of the outer surface of the specimen represented by figure 1h. 
lo. Enlargement of a portion of the outer surface of the type specimen, figure 1g. 
ip. Enlargement of a portion of the outer surface of the specimen represented by figure 1k. Figured by 
Walcott [189la, Pl. LXTIX, fig. 5e] as the surface of the specimen represented by figure 1m; and 
[1887, Pl. I, fig. 14b; and 188Gb, Pl. VIII, fig. 2c] as the outer surface of 1k. 
lq. Enlargement of a portion of the outer surface of the dorsal valve represented by figure 1m. Figured by 
Walcott [189la, Pl. LXTX, fig. 5f] as the surface of the valve represented by figure 1k; and [1887, Pl. 
I, fig. 14a] as the outer surface of 1m. 
Ventral valve from Locality 14s, Middle Cambrian Ogygopsis zone on Mount Stephen, British Columbia. 
Coll. Mr. Byron E. Walker, Toronto, Canada., Copied from Walcott [1908c, Pl. I, fig. 1]; see note 
under figures Id and le. 
1s. Enlargement by photography of a ventral valve from Locality 74, Middle Cambrian “‘Tonto” sandstone, 
Grand Canyon of the Colorado, Arizona. U.S. Nat. Mus. Cat. No. 51446b. 
1t. Enlargement by photography of a ventral valve from Locality 149a, Middle Cambrian limestones on Pole 
Creek, Madison County, Montana. U.S. Nat. Mus. Cat. No. 51445a. 
dr. 
4 
Micromitra (IPHIDELLA) PANNULA MALADENSIS (Walcott) (p. 364). 
Figure 2. Exterior of ventral valve from Locality 5b, Middle Cambrian limestone, 2 miles southeast of Malade, Idaho, 
showing pitting of surface, and obscure, radiating ridges. U.S. Nat. Mus. Cat. No. 51468a. 
2a. Apical view of ventral valve associated with valve represented by figure 2. U.S. Nat. Mus. Cat. No. 
51468b. 
18 
