428 NEW YORK STATE MUSEUM 



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moderately deep, the septa 3 mm distant and but little concave, the 

 septal necks extending about one fourth of the interseptal space 

 beyond the preceding septum. The siphuncle, upon emerging from 

 the nepionic bulb, rests against the wall of the conch, is tubular, 

 with circular section and a very slight interseptal inflation. 



Position and locality. In the coral facies of the dove-colored 

 Chazy limestone, exposed 2 miles west of Little ]\'Ionty bay near 

 Chazy village. 



Observations. The relations of Nanno to Caineroceras and 

 Vaginoceras have been fully discussed by the writer in the Report 

 of the State Paleontologist for 1904 [p. 322]. It suffices therefore to 

 state here why we have preferred to associate this form with Nanno 

 rather than with Vaginoceras. After the publication of Clarke's 

 observations on Nanno aulema, Holm referred several forms 

 with like nepionic bulbs, one of which he had before described as 

 Endoceras, to Nanno, treating the latter as a subgenus of Endo- 

 ceras [1896, p. 404]. Hyatt, however, has placed Endoceras 

 ^^Nanno) belemnitiforme Holm with Vaginoceras [1895, 

 p. 9] and based the genus Nanno on the presence of the endosi- 

 phuncle only at the apical end, and on the absolute contact of 

 siphuncle and conch on one side. Nanno noveboracum also 

 possesses this absolute contact, the septal funnels or necks entirely 

 disappearing upon the contact side. As to the presence of the endo- 

 siphuncle in the apical portion only we have not been able to satisfy 

 ourselves as fully as in regard to the other critical characters, but 

 the filling of the nepionic bulb with grayish calcite showing traces 

 of endosiphosheaths and of the siphuncle with white calcite of some- 

 what coarser texture without any traces of endosiphosheaths seems 

 to us to make the absence of the endosiphuncle the more legitimate 

 conclusion. We will add that in Nanno noveboracum the 

 siphonal necks or funnels clearly extend beyond the preceding 

 septum and hence have the V^aginoceras structure, but that after in- 

 spection of Clarke's types of Nanno aulema we have no doubt 

 t'nat a similar condition prevails in that genotype, and that also 

 there the septal funnels are slightly overlapping. 



Nanno noveboracum differs from N a n. n o a u 1 e m a in 

 the plumper form of the nepionic bulb, which, while having the same 

 length, is wider by one third just before the contraction; its apex 

 is also blunter. 



