90 FURTHER REMARKS ON AUSTRALIAN STROPHALOSIA , 
ribs on the back are in bundles of three, proceeding from a series 
of single nodes or tubercles at the sides ; here and there a rib 
will be much stronger than the others. 
The following is the detailed description of the Aucella. 
Genus AuCELLA. Keyserling, 1846. 
(Reise in das Petschora-Land, p. 297.) 
Gen. char. “Obliquely elongated, inequivalve, of thin structure, 
pearly within, and with 
Tam acquainted ; it is to all intents and purposes the same as the 
original by von Keyserling, 
By most authors Aucella is said to be a Jurassic genus, but 
AvcELta Liversipcer. Sp. NOV. 
steep, obliquely expanding ; posterior ear and hinge margin very 
; ventral margi 
2 pal. Indica, iii. p. 390. 
ar Up. Missouri (Smithsonian Contributions), by Meek and Hayden, 
