EXPLANATION OF PLATE XI. 
ay, 1. Cisikmrnodrs SWALLOVIANA, P 394. 
rom: view, —— the beak of opposite valve. 
d—View of the the front. 
¢—Rostral view, showing the depression in the umbo of the dorsal valve. 
Fig 2. CamERoPHoRIA BISULCATA, p. 296. 
peggy more elongated than usual. 
Fig. 3. SPrmRiFER SULCIFERUS, Pp. 293. 
e—View of the ventral valve. _ ) 
rastine Snir ah eerie 
tine 4. Sprrirer ais secieual p- 292. 
pase ioheey pie oe ee a, 
