210 
NAUTILOIDEA. 
“ The maximum width of the siphuncle, 20 mm., represents half 
of that of the shell at the smaller end of our fossils. On the other 
hand, at the larger extremity the reduced siphuncle does not occupy 
more than -i of the corresponding diameter, which reaches 54 mm.” 
{Barrancle.^ 
In his list of synonymy of S. docens, M. Barrande places A. num- 
mularium, Sow., sp., at the same time, however, expressing the 
opinion that in the absence of any evidence of a decrease in the 
diameter of the siphuncle of the latter it would be injudicious to 
unite the two species. 
Horizon, Etage E, bande 6 2 (= Salopian). 
Locality. Dworetz, Bohemia. 
Well represented in the Collection, which includes one of the 
specimens (fig. 3) figured by Barrande in the ‘ Bull. Soc. Ge'ol. de 
France,’ cited above. 
