PLATE 61. 
Cryptonblea rectirostra 
Page 
894 
Figs. 1-8. 
1. Dorsal view of a small elongated specimen, 
2-4. Dorsal, ventral and profile views of a larger and somewhat broader form. 
5. Ventral view of a specimen of large size. 
6-8. Ventral, dorsal and profile views of a broad unsymmetrical form of the ordinary size. 
Figs. 9-27. Cryptonella planirostra. 89a 
9-11. Dorsal, ventral and profile views of a young individual. 
12, 13. Dorsal and ventral views of a larger specimen. 
14-16. Dorsal, ventral and profile views of a specimen of the ordinary size and form of the 
species. 
17. Enlargement of the rostral portion of a ventral valve, showing the foramen, deltidial plates 
and teeth. 
18, 19. Dorsal and profile views of a much thickened and gibbous specimen. 
20-22. Dorsal, ventral and profile views of an unusually large specimen, which is much thick¬ 
ened, giving great gibbosity of form. This form is much less common than that of figs. 
14-16. 
23, 24., Dorsal and ventral views of a cast of this species, from the Hamilton group of Hardy 
county, Va., showing the form of muscular impressions. 
25. An enlarged ventral view of the loop of this species, showing its form and the existence of 
a,band across the dorsal side near the base of the crura. 
26. Dorsal view of a very large specimen referred with some doubt to this species. The specimen 
in this figure, is represented with the beak broken off', for the purpose of showing more 
clearly the filling of the rostral parts of the dorsal valve. The muscular impressions 
and groove left by the slender septum is faintly shown. 
27. Ventral side of the same individual, retaining the beak and showing the muscular impres¬ 
sions of this valve. 
Figs. 28-80. Cryptonella iphis. 896 
28-30. Ventral, dorsal and profile views of the specimen described. 
Figs. 31-41. Cryptonella (Terbbratula) eudora. 39S 
31, 32. Dorsal and ventral views of a small, thin specimen of the species. 
33. Dorsal view of a small individual, from the Waverly sandstones of Licking Co., Ohio, pre¬ 
senting all the specific characters of those from the Chemung group, of Hew York. 
34, 35. Casts of dorsal valves, showing the muscular impressions. 
36. Dorsal view of a cast, showing the cavities left by the removal of the teeth and dental 
lamellae. 
37-39. Ventral valves, showing a variety of form and proportions, resulting in some cases from 
distortion. 
40. Ventral view of a specimen from which the shell is removed in the upper part, and partially 
preserved below. 
41. Ventral view of an individual of the ordinary size, from the Waverly sandstones of Licking 
county, Ohio. 
(In the progress of this volume it has often been necessary to print the descriptions in advance of 
making up the plates, and in the present instance the descriptions were printed in ad¬ 
vance of the drawings of Terebratula and Cryptonella, and all the figures were 
referred to Plate 61. In consequence of a greater number of figures than antici¬ 
pated, it has become necessary to designate an additional Plate as 61 a.) 
