. A history of British mammals . well behind the ends of theascending branches of the premaxillae; in the American Beavers thenasals are shorter and terminate posteriorly at the level of thelachrymals. The mandible is strong and deep; its rami are very firmlyconnected with each other : the strong coronoid processes rise consider-ably above the rounded condyles; the angular processes are rathersmall, and their posterior tips rise above the level of the cheek-teeth. Dentition:—Both the incisors and the cheek-teeth when unwornshow traces of a former, primitive, tubercular or brachyodont structure
. A history of British mammals . well behind the ends of theascending branches of the premaxillae; in the American Beavers thenasals are shorter and terminate posteriorly at the level of thelachrymals. The mandible is strong and deep; its rami are very firmlyconnected with each other : the strong coronoid processes rise consider-ably above the rounded condyles; the angular processes are rathersmall, and their posterior tips rise above the level of the cheek-teeth. Dentition:—Both the incisors and the cheek-teeth when unwornshow traces of a former, primitive, tubercular or brachyodont tips of quite unworn incisors are very slender, rounded, andcoated on both their anterior and posterior surfaces with enamel; theyshow more or less distinct traces of apical tubercles and of grooves,which appear to represent the valleys which originally separated theincisor cusps; such parts are, of course, wholly ephemeral, and asvanishing structures betray a high degree of individual variability. 68o CASTORID^—CASTOR.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmammals, bookyear1910
