VGS31b is a highly-inclined ring galaxy found along a filament in a void ( ) .
Detailed photometry , by using u , g , r , i , z SDSS images , has shown that the overall morphology of VGS31b is very tricky , due to i ) the presence of a highly inclined ( 72 ^ { \circ } ) ring-like structure , which reaches the galaxy center tracing a “ spiral-like ” pattern , ii ) a one sided tail towards North-East and iii ) a bar in the central regions ( ) .
Such structure is reasonably the result of a “ second event ” in the evolution history of this galaxy , which could be a gravitational interaction with a companion galaxy or with the environment .

The main aim of the present work is to address the most reliable formation scenario for this object , by comparing the observed properties , i.e .
structure , baryonic mass , kinematics and chemical abundances , with the theoretical predictions .
In particular , we have used archival spectroscopic data , to derive the metallicity in the ring : we found a very low , sub-solar average value of Z = 0.3 Z _ { \odot } , comparable with other polar ring/disk galaxies , but lower than those measured for ordinary spirals of similar luminosity .
The study of the chemical abundances in polar ring/disk galaxies and related objects has received an increasing attention in recent years , since it has revealed to be a key-parameter to disentangle among the formation scenarios suggested for this class of objects : major merging , tidal accretion or cold accretion .
In the present work we check the cold accretion of gas through a “ cosmic filament ” as a possible scenario for the formation of the ring-like structure in VGS31b .