No. of true ribs 5 false ditto 2·1 ——— Total 8 OPETIORHYNCHUS VULGARIS. _Gray._ (Male.) The structure of the soft parts, both in this species of _Opetiorhynchus_, and the two following ones, so closely resemble that of _Furnarius_ and _Uppucerthia_, that one description will almost serve for the whole; those differences that do exist being not more than are generally found in species of the same genus; the external characters also being slight, I cannot but doubt the propriety of separating them; the cæca are slightly developed in this species, measuring ⅛ inch in length. Inches Length of œsophagus, proventriculus included 2½ of gizzard ⁶⁄₈ Breadth of ditto ½ Length of intestinal canal from gizzard to the cloaca 7½ from cæca to cloaca ⅞ Skeleton similar in form to that of _Furnarius cunicularius_. lines Length of sternum 11¾ Breadth anteriorly 5¼ posteriorly 7½ Depth of keel 3¾ of fissures 5 Breadth of ditto 1½ Length of pelvis 12²⁄₄ Breadth anteriorly 4 posteriorly 9¾ Length from occiput to point of bill 17 Breadth of cranium 7 Length of coracoids 8½ No. of cervical vertebræ 11 dorsal ditto 7 sacral ditto 11 caudal ditto 7 ———— Total 36 No. of true ribs 5 false ditto 2·1 ———— Total 8 OPETIORHYNCHUS ANTARCTICUS. _G. R. Gray._ (Male.) Structure of the soft parts as in _O. vulgaris_, but with the rectum of rather larger diameter, and the cæca very minute; gizzard filled with the remains of insects.