3o8 



NEW YORK STATE MUSEUM 



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Figure 5 of plate 7 [also text fig. 10] 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 ol 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 [^ .? z^] 

 we see the latter flanked on either side by 

 a series of two wings [w^ 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, more 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-i 



Fig. 13 Diagrammatic longi- 

 tudinal section of endosiphoco- 

 leon, to show its relation to 

 endosiphotube ^j;*, endosipho- 

 tube 



