History of North American pinnipeds, a monograph of the walruses, sea-lions, sea-bears and seals of North America . FIG. 55.—Cystopliora cristata. No. G576, Nat. Mus.; | nat. size. region is broad, regularly narrowing anteriorly. The teeth areremarkable for their small plaited (not lobed) crowns and thevery large size of the roots, which are not only long but greatlyswollen. Usually only the last (5th) upper molar is 2-rooted,and in this the double character of the root is only indicated by SKELETON AND SKULL. 731 the deep longitudinal grooves on each side. Not ^infrequently,however, the fourt
History of North American pinnipeds, a monograph of the walruses, sea-lions, sea-bears and seals of North America . FIG. 55.—Cystopliora cristata. No. G576, Nat. Mus.; | nat. size. region is broad, regularly narrowing anteriorly. The teeth areremarkable for their small plaited (not lobed) crowns and thevery large size of the roots, which are not only long but greatlyswollen. Usually only the last (5th) upper molar is 2-rooted,and in this the double character of the root is only indicated by SKELETON AND SKULL. 731 the deep longitudinal grooves on each side. Not ^infrequently,however, the fourth upper molar is either distinctly double-rooted, or iucipiently so, the two fangs being connate and moreor less completely united. It sometimes happens that the 4thupper molar is double-rooted on one side and single-rooted onthe other. In old age the bones of the skull become greatly. FIG. 56.—Cystophora cristata. No. 6576, Nat. Mus.; | nat. size. thickened, the surface assumes a more or less rugose charac-ter, with incipient sagittal and well-developed occipital sutures, even in old age, remain open nearly throughoutthe skull. The usual sexual variations are observable in the smallersize, weaker structure, and smoother surface of the bones in thefemales. An adult female skull gives a length of 220 a length of 275 mm. in an old male. Detailed measure-ments are given in the subjoined table. 732 CYSTOPHOEA CRISTATA—HOODED SEAL. 6 be •4 •JBiom ^SBI 0} smuitt jo 93pa f j9AiOi jo •98BO-arBiq jo qjpm ^sa^gjf) • jo q J° jo qjpBaag; M fa£ 3 - 3 300. t»a f>a »O in h 3 ® 0) ° ,g J3 >> t8 !« » M K >• c* •* m TI< m oo IO TX ^ O 00 O ^H i— 1 00 CO O OOS 00 00 CO OJ 00 1O O OiH CO O o oo o m^j< co ^t in «O m O IN <o •* I ,3 oom 89JBH joijg^eod jo jo J° ^B sanoq q^pm eaaoq JBSBJJ o «o M ^H co •
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherwashingtongovtprin
