REPORT OF THE STATE PALEONTOLOGIST I903 



311 



esb 



formed portion of the endosiphocoleon as a free standing black 

 and conchiolinous tube^ [see text fig. 15]. This shows that here the 

 endosiphocoleon is not a mere continuation of the apex of the endo- 

 siphocone, as it was found in Vaginoceras belemniti- 

 forme but a new formation, growing within the apical part of the 

 visceral cone, presumably preparatory to a succeeding withdrawal 

 of the animal from that part of the 

 siphuncle and the formation of a 

 new endosiphosheath. 



Two sections which exhibit the 

 same features are those reproduced 

 in plate 7, figure i and plate 9, 

 figure I. These possess on both 

 narrow sides of the endosiphocoleon 

 a series of two black concentric 

 crescents which are not in contact 

 with it. In some of these specimens 

 [pi. 7, fig.i] the innermost of these 

 crescents can be directly traced along 

 the longitudinal sections to the 

 strong conchiolinous wing or lat- 

 eral staff of the endosiphosheath 

 described above [see text fig. 14]. 



Directly germane to the sections 

 and diagrams given here and illus- 

 trative of the formation and charac- 

 ters of the wings of the endosi- 

 phocoleon is the section in plate 8, 

 figure 7. In this the apical part of the endosiphocone is transected 

 and its semicircular outline shown in the center of the figure and its 

 base, which corresponds to the flat or outer (ventral?) side of the 

 siphuncle, is drawn out into short, obliquely ascending horns. The 

 wall of the cone is formed by the endosiphosheath which is con- 

 tinued in the direction of the horns to the wall of the siphuncle and 



esh 



Fig. 15 Diagrammatic section of si- 

 phuncle to show relation of endosiphoco- 

 leon [esv] to endosiphocone [esk]. Endo- 

 siphocone cut through minor axis: esd, 

 endosiphoblade ; esc, endosipholining : 

 ess, endosiphosheath 



^It is twice as long as the lithographer's reproduction. 



