OCR Text |
Show 408 MR. W. P. PYCRAFT ON THE [Mar. 21, b. Size larger, not less than 2\ in. (Bulweria alone excepted); postacetabular ilium with dorsal border well-defined and terminating in a well-marked spine. c . Pre-ilium moderately broad and expanded distally, resting upon the synsacrum and partly concealing it; ischium having its free end more or less sharply deflected. e". Post-ilium with flattened dorsal aspect, rapidly tapering to form a laterally-compressed blade-like edge, terminating in a spine; obturator foramen an elongated oval twice length of the acetabulum ; free end of ischium bent at right angles to long axis, narrow and tapering to a point Puffinus. Majaqueus. / . Post-ilium slightly or not at all compressed dorsally; pubis projecting distinctly beyond the ischium ; ischium with broad flattened foot closely articulating with pubis. c3. Ischiadic foramen nearly circular; dorsal border of pre-ilium concave. c4. Width of dorsal aspect of post-ilium rapidly decreasing from before backwards; post-iliac spine ill-defined ... Thalassceca. d4. Width of dorsal aspect of post-ilium broad throughout; post-iliac spine well-defined Priocella. d3. Ischiadic foramen oval; dorsal border of pre-ilium straight. e4. Thoracic vertebra immediately in front of pre-ilium fused with synsacrum. ft5. Entire length of pelvis not less than 3£ in Fulmarus. b\ Entire length of pelvis not exceeding 2j in Daption. e3. Lumbar enlargement forming a distinct tumid swelling in front of acetabulum. /*. Ischium never completely fused with pubis posteriorly. c5. Anterior border of pre-ilium obliquely truncated; ischium tapering to a fine point CEstrelata. d5. Anterior border of pre-ilium squarely truncated ; ischium of equal width throughout Bulweria. y*. Pubis completely fused posteriorly with ischium ... Prion. d'. Pre-ilium reduced to narrow bars, separated one from another by the whole width of the synsacrum ; ischium in the form of a long slender spine running directly backwards Pelecanoides. B. Pre-ilia meeting in the mid-dorsal line above the synsacral neural crest • suture dividing innominate bones from synsacrum almost or quite obliterated. ^ a. With a more or less well-marked pectineal process; free end of ischium turning downwards in a strong curve; pubis of uniform thickness throughout; cavity of pelvis not divided into anterior and posterior renal lossas A r Ussijraga. b. N o pectineal process ; free end of ischium not abruptly curved ; cavity of pelvis distinctly divisible into anterior and posterior renal fossas; ribs oi sacral vertebras extending across renal cavity immediately behind acetabulum Diomedea, E. PECTORAL LIMB. Humerus with a shallow coraco-humeral groove; a triangular pectoral crest not extending far down the shaft; crista inferior very small, formed for the most part by the downwardly-directed tubercuium inferius; with a large ectepicondylar process, aud a more or less deep fossa for the brachialis interims ; the sub-trochanteric fossa is in no case of more than medium size, and never subdivided into two ; the ulna is without an olecranon process; the phalanx of the pollex and the 2nd phalanx of M c . II. are of great length. |