2 BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



Genus NONION Montfort, 1808 



Nonion Montfort, Conch. Syst., vol. 1, 1808, p. 211. — Cushman, Special 

 Publ. No. 1, Cushman Lab. Foram. Res., 1928, p. 204. 



Melonis Montfort, Conch. Syst., vol. 1, 1808, p. 67 (genoholotype, 

 Nautilus pompilioides Fichtel and Moll). 



Florilus Montfort, Conch. Syst., vol. 1, 1808, p. 135 (genoholotype, 

 Nautilus asterizans Fichtel and Moll). 



Pulvinulus (part) Lamarck, 1816. 



Placentula (part) Lamarck, 1822. 



Cristellaria (part) Lamarck, 1822. 



Lenticulina (part) Defrance, 1824 (not Lamarck). 



f*olystomella (part) Defrance and Authors (not Lamarck). 



Nonionina d'Orbignt, Ann. Sci. Nat., vol. 7, 1826 (genotype, by designa- 

 tion. Nonionina umbilicata d'Orbigny). 



Genoholotype. — Nautilus incrassatus Fichtel and Moll. 



Test free, planispiral, more or less involute, bilaterally symmetrical, 

 periphery broadly rounded to acute; chambers numerous; wall finely 

 perforate; aperture, an arched, usually narrow opening between the 

 base of the apertural face and the preceding coil. 



Carboniferous (?) to Recent. 



Most of the species of Nonion are simple in their structure, 

 without a canal system, usually with little ornamentation and not 

 reaching any great size. The passage to ElpJiidium is a gradual 

 one and there are some species of the latter which do not develop 

 the retral processes until toward the end of the growth of the test 

 and which in their early stages would be classed as Nonion. This 

 seems to be the most primitive genus of the group. 



NONION (?) UMBILICATULUM (Walker and Jacob) 



Plate 1, figures 1 a-b 



"Nautilus spiralis umbilicatus sulcatis" Walker and Boys, Test. Min., 



1784, pi. 3, fig. 69. 

 Nautilus umbilicatulus Walker and Jacob, Adams's Essays, Kannmacher's 



ed., 1798, p. 641, pi. 14, fig. 34. 



A reproduction of the original figure is given here. There is much 

 uncertainty regarding this species. As will be seen by the figures, 

 the two sides are evidently not the same. Parker and Jones com- 

 mented on this figure as follows: "Figure 69 is a common form of 

 Truncatulina lohatula, having the outline of the cells uniform or 

 flush; the septal lines being merely 'furrowed.' According to Walker, 

 it was from Sandwich — not common." 



"Montagu, (Test. Brit. Suppl. p. 78), refers to this figure when 

 describing a little Nonionina; and Williamson (Monogr. p. 42), 

 makes it a Polystomella. We believe that they must both be wrong, 

 because in the specimen figured by Walker the two faces are decidedly 

 unsymmetrical." 



