i 
PLATE XXXII. 
Mesothyra Oceani. 
Page 187. 
1. An outline restoration drawn from the large right valve represented on plate 33, fig. 4, showing 
the jn-obable character of the articulation of the valves of the carapace, the position and rela¬ 
tive size of the rostral and dorsal plates, the number of abdominal segments and the setiferous 
caudal spines. 
2. The optic node of the specimen represented on jdate 33, tig. 4, enlarged to three diameters, show¬ 
ing the deep circulai- pit at its summit. 
3. A similar enlargement of the optic node of the valve shown on plate 33, fig. 5. 
4. A portion of the carina on the valve represented upon plate 33, tig. 4, enlarged to three diameters. 
The lateral slopes are divided by a sharply impi-essed longitudinal line into a punctate lowei- 
portion and an impunctate, gently crenulated summit. 
. 0 . A portion of the right cercopod of the post-abdomen shown on plate 34, tig. 4, enlarged to three 
diameters; showing the impressions of the setae, their bases of attachment along the inner 
margin of the spine and the coai-sely tubercled and ridged surface. 
6. The hinge angle of the right valve figured on plate 33, tig. 4, enlarged to three diameters; show¬ 
ing the thickened apex, curved upward and inward for articulation with the left valve, and the 
tubercled and punctate surface. 
Mesothyra Neptuni. 
Page 191. 
Fig. 7. A portion of the right cercopod of the specimen represented on plate 33, tig. 1 ; di-awn to show 
more distinctly the character of the surface ornamentation. 
Hamilton group. Plainfield, Otsego county. 
Mesothyra spum^a. 
Page 193. 
Fig. 8. A nearly entire caudal spine of this species. 
Fig. 9. A portion of the same, enlai-ged to three diameters, to show the character of the surface oi-namen- 
tation. 
Hamilton group. Delphi, Onondaga county. 
Fig. 
Fig. 
Fig, 
Fig. 
Fig. 
Fig. 
