  We derive explicit Bayesian nonparametric analysis for a species sampling
model with finitely many types of Gibbs form of type $\alpha= -1$ recently
introduced in Gnedin (2009). Our results complement existing analysis under
Gibbs priors of type $\alpha \in [0, 1)$ proposed in Lijoi et al. (2008).
Calculations rely on a groups sequential construction of Gibbs partitions
introduced in Cerquetti (2008).
