PLATE IV—Continued. 
KUTORGINA, Billtngs. 
Page 90. 
Kutorgina cingulata, Billings. 
Fig. 10. The pedicle-valye of an example with a low, scarcely incurved beak. X 2. 
Fig. 11. The brachial valve. X 2. 
Fig. 12. Profile of a pedicle-valve from which the shell is largely removed; showing the degree of incurv¬ 
ature. X 3. 
Fig. 13. A pedicle-valve with a strongly incurved umbo ; drawn from an internal cast. X 3. 
Fig. 14. Profile of the same. X 3. 
Fig. 15. A brachial valve; drawn from a gutta-percha impression of a natural mould of the exterior. 
Natural size. 
Fig. 16 . The interior of a brachial valve ; showing the radiate ornamentation of the surface and the faint 
muscular ridges near the beak. X 2. 
Fig. 17- A brachial valve in which the cardinal margin is not transverse, as in the, pthpr examples fig¬ 
ured, but is strongly reentrant. X 2. 
Georgia group. Swanton, Vermont. 
Kutorgina Latourensis, Matthew. 
Fig. 18. A pedicle-valve ; drawn from a gutta-percha cast from a natural mould of the exterior. X 6. 
Fig. 19. Profile of the same. X ' 6 . 
Fig. 20. Cardinal view of the same; showing the open triangular fissure. X 6. 
St. John group. Portland, New Brunswick. 
MESOTRETA, Kutorga. 
Page 109. 
Mesotreta tentortum, Kutorga. 
Fig. 21. The pedicle-valve; copied from KuTORGA’s.work, Ueber die Brachiopodenrfamilie der Siphonp- 
tretsese, pi. vii, fig. 4c. 
Lower Silurian. Russia. 
SIPHONOTRETA, Verneuil. 
Page 110. 
SlPHONOTRETA UN GUICUL AT A, Verneuil. 
Fig. 22. Cardinal portion of the pedicle-valve; showing the inner extension of the sipho, which is appar¬ 
ently atrophied and caecal. 
Fig. 23. A similar portion of another valve in which the sipho is open. 
(Kutorga, op. cit., pi. vi, fig. 3, a, b.) 
Fig. 24. A portion of the shell near the anterior margin, much enlarged to show the tubular structure, the 
epidermal layers and the modfe of origin of the hollow spines. I( 
(Kutorga, op. cit., pi. vi, fig. 2c.) : >J 
Figs. 25, 26. The interior characters of both valves as given by Davidson. 
(Geological Magazine, 1877, pi. ii, figs. 9, 11.) 
SCHIZAMBON, Walcott. 
Page 113. 
Schizambon typicalis, Walcott. 
Fig. 27. The interior of a pedicle-valve ; showing an oval foramen with the groove or depressed track, and 
diverging lateral muscular ridges. X 5. 
Fig. 28. The exterior of a brachial valve ; showing the radiating and concentric strise. In this specimen 
' the, surface appears finely granulosa* the granulations probably being the bases of minute 
spinules like those represented by Mr. Walcott (Palseont. Eureka Dist., pi. i, fig. 3d). 
Fig. 29. The interior of a brachial valve; showing the outline of the mtiscular area and its subdivision 
by diverging ridges. X 5. 
Fig. 30. Another interior of a brachial valve, differing from the foregoing in the less conspicuous division 
of the muscular area. The inner pair of diverging ridges terminate anteriorly in deeply col¬ 
ored, oval areas, which are too strongly elevated in the figure. X 5. 
Lower portion of the Pogonip group. Eureka District, Nevada. 
