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PLATE I. 
Streptelasma strictum. 
Page 1. 
1. An individual of the ordinary or prevailing size. 
2. A lateral view of an individual of somewhat smaller size, showing the rapid increase of lamellae 
by interstitial additions along a single line upon one side of a continuous ray. 
3. Anterior view of another individual where the rays increase by additions on one side of the 
anterior ray. 
4. An unusually large individual of the species, showing a rapid increase in the number of rays on 
one side, for some distance from the base, above which point the increase takes place in another 
part of the coral. 
5. An individual showing an increase by successive budding—-a rare condition in the Helderberg 
and Schoharie regions, but common in some other localities. 
6. A longitudinal section showing the vertical lamellae which are somewhat complicated at the center, 
but without transverse septa. 
7. The calyx of a well-preserved specimen showing the disposition of the lamellae. 
8. An enlargement of the calyx from another specimen in which the arrangement of the lamellae is 
very distinctly shown. 
9. A vertical section of a specimen showing a central columella. 
10. A transverse section below the base of the open calyx showing the disposition of the lamellae. 
Lower Helderberg group. Clarksville, JS T . Y. 
Zaphrentis Rcemeri. 
Page 2. 
Fig. 11. A lateral view of a specimen of the ordinary or prevailing size and form, showing the intermittent 
growth usually characteristic of the species. 
more elongate and less regular form which has expanded much less rapidly in its progress of 
growth than the prevailing forms. 
The calyx of a specimen where the anterior ray is not conspicuous. 
A calyx where the anterior ray is obscurely marked a little on one side of its usual position. 
A calyx where the condition of growth presents the transverse septum over a considerable portion 
of its area, the lamellae not having extended to the center. The anterior fosette is conspicuous. 
An individual which has been broken so as to exhibit the transverse septa. 
A specimen broken longitudinally and showing numerous closely arranged tabulae in the central 
portion, with the lamellae well preserved in the upper part of the calyx. 
Lower Helderberg group. Clarksville, N. Y. 
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