Thecospira, II, 73 (821). 
Tomasina,'I, 99 (231). 
Torynifer, II, 195 (943). 
Trematis, I, 126 (258). 
Trematobolus, I, 119 (251). 
Trematospira, II, 50 (798). 
Trigeria, IT, 108 (856). 
Trigonosemus, If, 140 (888). 
Trigonotreta, II, 3 (751). 
Trimerella, I, 104 (236). 
Triplecia, I, 157 (289). 
Tropidoleptts, II, 122 (870). 
Uncinella, II, 46 (794). 
Uneinulina, II, 80 (828). 
Uncinulus, II, 80 (828). 
Uncites, II, 43 (793). 
BRAOHIOPODA. 943 
Ungula, I, 110 (242). 
Ungulites, I, 110 (242). 
Verneuilia, II, 14 (762). 
Vitulina, IT, 56 (804). 
Volborthia, I, 117 (249). 
Waldheimia, II, 131 (879). 
Waltonia, I1, 141 (889). 
Whitfieldella, II, 18 (766). 
W hitfeldia, II, 22 (770). 
Wilsonia, II, 79 (827). 
Zeilleria, IT, 135 (883). 
Zellania, II, 149 (897). 
Zdimir, Il, 94 (842). 
Zugmayeria, II, 130 (878). 
Zygospira, II, 64 (812). 
ADDENDA. 
Orthotropia, Hall, 1894. 
(For illustration see Paleontology of New York, Vol. VIII, part 2, pl. 84, 
figs. 3-7.) 
Elongate biconvex shells with short hinge, erect cardinal area, 
open delthyrium, deep muscular scar in the pedicle-valve forming 
a sessile spondylium from the anterior extremity of which 
extends a short median septum. There is also a median septum 
in the brachial valve. 
Type, Orthotropia dolomitica, Uall. Niagara group. 
Torynifer, Hall, 1894. 
(For illustration see Paleeontology of New York, Vol. VIII, part 2, pl. 84 
figs. 34, 35.) 
Shells athyroid in external aspect, but with a well-defined 
cardinal area and a distinct spondylium in the pedicle-valve 
supported by a median septum. 
Type, Zorynifer criticus, Hall. Lower Carboniferous (St. 
Louis group). 
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