XXVIII.—Studies on the Charadriiformes.–I. on the Systematic Position of the Ruff. (Machetes pugnax) and the Semipalmated Sandpiper (Ereunetes pusillus), together with a Review of some Osteological character which differentiate the Eroliinœ (Dunlin group) from the Tringinœ (Redshank group).