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Show 994 PROF. n'ARCY W. THOMPSON ON [Dec. 18, arms, the ventral ones in the ventral and ventrolateral arms, converge to unite with the buccal membrane, drawing it outwards at their points of attachment into pouched hollows, above which its free margin is produced into pointed lobes. A similar arrangement is seen in Jatta's figure of Thysanoteuthis rhombus Tr., in the Naples Monograph, pi. ix. fig. 6.' In Ommastrephes the buccal membrane is six-lobed, the anterior and posterior lobes each corresponding to the attachment of two adjacent bridles from Fig. 1. A. Upper mandible of Ancistroteuthis. Natural size. B. Lower mandible of Ancistroteuthis. Natural size. the arms ; and each of these lobes is furnished with two small two-rowed clumps of small suckers. Here the suckers are absent, and the attachments of the two ventral fringes are widely separate, so that the buccal membrane is seven-lobed. The fringes above-mentioned, that lie adjacent to the suckers, are narrow in the case of the ventral arms, but considerably broader in the other |
