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Show 1874.] GIGANTIC CEPHALOPODS. 493 served in the British Museum, which may prove of service to Prof. Verrill for comparison with the fine series to which he enjoys facility of access. The length of this arm, from one extremity to the other, is just 9 feet; the circumference at the base 11 inches; and from this it gradually decreases, terminating in a fine point. The suckers are arranged in two rows throughout the extent of the arm, numbering, approximately, 150 to each row, or a total of 300 to the whole organ. Forty-three suckers only are stationed on each side in the first or proximal half of the arm; one hundred on each side occupy the whole length, with the exception of 14 inches, this smaller length including the remaining fifty on each side, which are very minute and crowded together. The comparative distances between the suckers throughout the whole length in each row are as follows :- between the first and second sucker, 1^ inch; halfway up the arm, 1 inch; at three quarters of the entire length, \ inch; and within six inches of the distal extremity, \ inch. The relative diameters of the suckers at similar distances are:-at the base, extreme outside measurement | inch, inside measurement of corneous ring \ inch; and, those suckers a little past the first few being the largest, halfway down ^ inch outside and \ inch inside measurement, at three quarters length \ inch, and at 6 inches from the extreme point |- inch outside measurement, gradually diminishing from here to the size of a pin's head. The shape and structure of the suckers upon this British-Museum specimen agree with those of Ommastrephes todarus as given by D'Orbigny, corresponding also with those figured by Harting, referred by him to the same species, and anticipated by the same authority to be also identical with Prof. Steenstrup's Architeuthis dux. More minutely they may be described as hemispherical in shape, the stalk or peduncle being attached laterally at the base of the hemisphere, the point of insertion of the same in the cup being marked by a conspicuous pit-like depression. The horny ring is obliquely set, and much deeper at the side opposite the insertion of the stalk ; the inner margin is serrated; and in most examples the serratures bordering the deeper side are considerably larger than in the other portions of the circumference ; in some instances the serratures, except at the particular point mentioned, are altogether aborted, having the inner margin of the ring quite smooth ; in other examples, and more especially among the larger suckers, the teeth or serratures are equal or subequal. The average number of the teeth of the largest rings is twenty. W e may further mention, then, in conclusion, that the arm preserved in the British Museum belongs to a species apparently identical with Ommastrephes todarus of D'Orbigny, which, according to M . Harting, is synonymous with Prof. Steenstrup's Architeuthis dux. A comparison of the form and armature of the suckers of this example with the Newfoundland series will therefore be of much service towards ascertaining whether any identity exists between the two, although, from the evidence already adduced, this |