This paper initially received scores of 7,7,7, and 5, and after the rebuttal R4 revised up from a 5 to a 6. The reviewers all commented in the discussion that they were satisfied with the responses they received in the rebuttal. The problem of discovering hidden unlabelled subclasses in labelled datasets is an interesting one and relevant to a general machine learning audience. The authors are encouraged to use the suggestions in the reviews to improve the clarity of the paper e.g. R1's comment about the clustering step, fix the typos (R2), and polish the figures (R3, R1).