PLATE LXXIV. 
(Figures 1-9 by R. P. Whitfield.) 
Genus AMPHIGENIA, Hall. 
Page 252. 
See Plate 73. 
Amphigenia elongata, Vanuxeni. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Figs. 
Fig. 
1. Dorsal view of a partial cast; showing the muscular impressions and vascular sinuses of the 
brachial valve, and the cavity left by the medially divided hinge-plate. 
Corniferous limestone. Clarence, New Ym'k. 
2. Cardinal view of an internal cast; showing- the filling of the spondylium and of the visceral fora¬ 
men, and the cavities left by the median septum and hinge-plate. 
3. Median longitudinal section of both valves; showing the degree of development of the spondy¬ 
lium, median septum, and septal plates; also the g-reat thickness of the shell in the umbonal 
region of the brachial valve and the length of the crura, with their convex terminal expansion. 
Corniferous limestone. Le Hoy, New Ywk. 
4. Dorsal view of an individual of medium size with regularly elliptical form and finely striated 
surface. 
5. An internal cast of the umbonal portion of the bi-achial valve; showing the septal plates, the four 
sharply defined scars of the adductor muscles, the ^•■ascular sinuses and genital markings. 
Corniferous limestone. Western New York. 
6. The exterior of a brachial valve having the charactei-istic subovate outline. 
7. 9. Dorsal and profile views of a shell of full medium size with gibbous valves and finely striated 
surface. 
Corniferous limestone. Cayuga, Ontario. 
8. Internal cast of a large brachial valve ; showing the muscular impression and the cavity left by 
the removal of the hinge-plate. 
Corniferous limestone. Le Roy, New York. 
