PLATE I. 

 Stkeptelasma stkiotum. 



Page 1. 

 An indi\-idual of the ordinary or prevailing size. 

 A lateral view of an individual of somewhat smaller size, showing the rapid inci-ease of lamellae 



by interstitial additions along a single line upon one side of a continuous ray. 

 Anterior view of another individual where the rays increase by additions on one side of the 



anterior ray. 

 All unusually large indiNadual 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. 

 An individual showing an increase by successive budding — a rare condition in the Helderberg 



and Schoharie regions, but common in some other localities. 

 A long^itudinal section showing the vertical lamellae which are somewhat complicated at the center, 



but without transverse septa. 

 The calyx of a well-preserved specimen showing the disposition of the lamellae. 

 An enlargement of the calyx from another specimen in which the an-angement of the lamellce is 



very distinctly shown. 

 A vertical section of a specimen showing a central columella. 



A transverse section below the base of the open calyx showing the disposition of the lamellae. 

 Lower Helderberg gi-oup. Clarksville, N. Y. 



Zapheentis R(EMERI. 



Pago 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. 

 Fig. 12. A more elongate and less regular form which has expanded much less rapidly in its progress of 



growth than the prevailing forms. ^ 



Pig. 13. An individual of unusually large size, preserving the epitheca almost entire. 

 Fig. 14. A very large individual from which the epitheca has been principally i-emoved. 

 Figs. 15, 16. The calyx in specimens where the depression of the anterior ray is sti-ongly marked. 

 Fig. 17. The calyx of a specimen where the anterior ray is not conspicuous. 



Fig. 18. A calyx whei-e the anterior ray is obscurely marked a little on one side of its usual position. 

 Fig. 19. A calyx where the condition of growth presents the transveree septum over a considerable portion 



of its ai-ea, the lamellse not having extended to the center. The antei-ior fosette is conspicuous. 

 Fig. 20. An individual which has been broken so as to exhibit the trausveree septa. 

 Fig. 21. A specimen broken longitudinally and showing numerous closely arranged tabulae in the central 



portion, with the lamellse well preserved in the upper part of the calyx. 

 Lower Helderberg group. Clarksville, N. T. 



