PLATE .LXII. 
(Figures 1-5, 8-10, U-16, 21-23, 37-45, 52, .53 by E. EMMONS ; 7, 8, 11-13, 17-20, 24-3(i 46-51 by G. K. .SuiPSON.) 
Genus SYNTROPHIA, gen. nov. 
Page 21(5. 
Synthophia lateralis, Wliitiiekl. 
Fig. 1. The exterior of a pedicle-valve ; sho5ving the long, straight hinge and broad median sinus. 
’Fig. 2. The exterior of a brachial valve ; showing the broad, obscure median fold. 
Fig. 3. The exterior of a small pedicle-valve. 
Fig. 4. A portion of the interior of the pedicle-v'alve ; showing the cardinal area and spondylium. X 3. 
Fig. 5. Cardinal view of conjoined valves which have been transversely sectioned in the umbonal i-egion ; 
showing the spondylium in both valves. The shell has been cut just in front of the support¬ 
ing septa, the brachial valve being above. X 2. 
Fig. 6. Cardinal view of the specimen representeil in tig. 1 ; showing the cardinal area. 
Figs. 7, 8. Internal casts of two brachial v.alves wth impressions of vascular sinuses. 
Fig. 9. A portion of the interior of the pedicle-valve ; showing the complete spondylium and the division 
of its surface into median (adductor) and lateral (diductor) muscular areas. X 3. 
Fig. 10. Oblique view of the specimen represented in tig. 1; showing the elevation of the spondylium and 
the length of its supporting median septum. 
Calciferous formation (Fort Cassin beds). Fort Cassin, Vermont. 
Genus CAMARELLA, Billings. 
Page 219. 
Camarella Volrorthi, Billings. 
Figs. 11, 12. Dorsal views of two shells ; showing a slig-ht dift'erence in outline and very faint median mar¬ 
ginal plication. 
Trenton limestone. Jacksonhurgli, N. Y 
Figs. 13, 14, 15, 16. Profile, dorsal, ventral and front views of a more strongly plicated shell. X 2. 
Fig. 17. Cardinal view of conjoined valves which have been transversely sectioned in the umbonal region ; 
showing the spondylium of the pedicle-valve and its median supporting septum. X 4. 
Fig. 18. 'J'he interior of the urnlional portion of the brachial valve ; showing the small apical spondylium 
and the median septum. X 4. 
Black River limestone. Paiiqnette’s Rapids, Ottawa River. 
Camarella Panderi, Billings. 
Figs. 19, 20. Dosral and front views of an average example. 
Figs. 21, 22, 23. Dorsal, front and profile views of an individual with no ti-ace of lateral or marginal plica¬ 
tions. X 2. 
Black Rivei’ limestone. Panquette's Rapids, Ottawa River. 
Genus SYNTROPHIA. gen. xNOv. 
Page 216 
SyNTROPHIA (?) CALCIFERA, BillillgS. 
Fig. 24. The exterior of the pedicle-valve; showing the elevated umbo, deep median sinus and extended 
hinge-line. X 2. 
Quebec grouii. Pointe Levis, Canada. 
