Column headings: _B. arnuxii._ A: New Brighton, New Zealand (Flower). No. 3. B: New Zealand (V. B. and Gerv.). (Type). ([a]) C: 21511, U.S.N.M., New Zealand, young. _B. bairdii._ D: 49726, St. George Island, female, adult. E: 49725, Centerville, California, male(?) adult. F: 20992, Bering Island, (Type). G: 49727, St. George Island, male, young. H: Mounted skull, Bering Island(?) (Grebnitzki?). A B C D E F G H mm. mm. mm. mm. mm. mm. mm. mm. Total length of 1,372 1,392 [b]1,174 1,524 1,423 1,378 1,062(?) 1,474 skull Height from vertex 533 494(?) 493 563 544 ... ... 575 to inferior border of pterygoids Breadth across [c]625 684 577 766 682 662 530 [716] middle of orbits Breadth across 686 748 606 808 722 ... 560 [760] postorbital processes Breadth across 671 748 584 750 675 ... 520 [740] zygomatic processes Length of rostrum 919 894 800 960 925 880 578+ 1,025 Breadth of rostrum 399 414 378 475 420 428 310 429 at base Breadth of rostrum 152 150 149 207 197 188 ... 223 at middle[d] Length of premaxillæ ... .... ... ... ... ... ... ... Breadth of 91 90 101 120 119 115 ... 125 premaxillæ at middle[d] Greatest breadth of 208 210 189 235 217 238 187 239 premaxillæ in front of nares Greatest breadth of ... 246 193 215 195 181 165 197 premaxillæ behind nares Distance from 1,097 1,080 935 1,185 1,130 ... 720+ 1,187 anterior end of premaxillæ posterior end of pterygoids (median) Distance from 345 264 252 276 270 260 115+ 307 anterior end of premaxillæ to anterior end of vomer Length of portion ... 420 253± 535 370 472 360± 450 of vomer visible on palate Length of nasals 132 162(?) 134 135 118 135 98 142 (greatest, median, straight) Breadth of nasals 102 180 125 119 97 105 90 105 (greatest) Breadth of anterior 74 102 80 110 98 96 83 100 nares Breadth of foramen 61 ... 72 85 82 84 83 71 magnum Breadth across 191 213 186 261 228 240 195 235 occipital condyles Breadth of each ... ... 75 123 104 108 83 98 condyle Height of each ... ... 135 193 171 168 142 178 condyle