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NEW YORK STATE MUSEUM 



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Figure 5 of plate 7 [also text fig.io] shows the small, thick 

 walled endosiphotube [e s t] contained within the endosipho- 

 coleon [e s v], which is entirely filled with very dark organic 

 carbonate of lime. This observation suggests that the endosi- 

 photube is not a narrower apicad continuation of the endosipho- 

 coleon, but a new formation within the same ; an inference which 



is borne out by the observation of such sec- 

 tions as that reproduced in figure 2, in 

 which a still incomplete tube is shown 

 within the open lumen of the endosiphoco- 

 leon. This latter stage is also represented 

 by the diagrammatic section text figure 8. 

 Besides the inceptive endosiphotube [est] 

 and the inclosing endosiphocoleon [e s v] 

 we see the latter flanked on either side by 

 a series of two wings [u\ and W2] which 

 have formed on two successive endosipho- 

 sheaths. In text figure 9 only one of these 

 wings, the outer and older is present. In 

 order to make this peculiar relation of 

 endosiphocoleon and endosiphotube still 

 clearer we have added two longitudinal 

 diagrammatic sections. Text figure 13 

 shows the outer, m.ore anteriorly situated 

 endosiphocoleon and the inner endosipho- 

 tube, and text figure 14 illustrates the posi- 

 tion of the successive wings [w] on the 

 endosiphoshaths [ess]. A condition as 

 that illustrated in text figure 8, when two 

 wings embrace each other could be obtained 

 by a transverse section in a plane, laid through the middle of the 

 longitudinal section figure 14. We shall recur more fully to the 

 relation of endosiphocoleon and endosiphotube. 



Figure 3 of plate 7 is a section 5 mm distant from figure i. 

 Between figure 3 and figure 5 (10 mm) a very abrupt quarter 

 turn of the entire endosiphocoleon takes place, so that its hori- 



Fig. 13 Diagrammatic longi- 

 tudinal section of endosiphoco- 

 leon, to show its relation to 

 endosiphotube est. endosipho- 

 tube 



