OCR Text |
Show 1881.] THE SURVEY OF H.M.S. 'ALERT.' 25 greater in L. gahi, and their form, judging from the figure of them, more acute. The form and attachment of the fins to the back are very similar in L. brasiliensis and L. patagonica. The former, however, is a broader species, has a differently shaped shell, and several other differences. ONYCHOTEUTHIS INGENS, sp. n. (Plate III. figs, l-l d.) Sab. Port Riofrio, west coast of Patagonia. The head only of a species of this genus was sent by Dr. Coppinger. It differs in certain particulars from the known species, and is especially interesting on account of its great size. Description. Of the arms, the upper or dorsal pair are most slender and the shortest, the two lateral pairs about equal in thickness, the upper pair having a slight advantage in length, in this respect agreeing with the lower or ventral pair, which, however, are a trifle broader at the base than any. The latter arms have a remarkably broad and almost flat outer surface, and are roundly angled at the margins; the sides are flattened and converge, so that the inncrside, likewise flat, becomes but little broader than half the outside ; the outer margin is provided with a broad membranous expansion, which apparently extends to the extremity of the arm: it is widest at the base, where it connects the adjoining arm, gradually narrowing towards the tip. Lower lateral pair also furnished with a membrane on the upperside, which, however, is very much the broadest near the middle of the arm. The upper lateral pair are provided with a membrane on the lower side ; but it is very narrow ; and the dorsal pair are destitute of any. The suckers are arranged in two alternating series, commencing a short distance (about an inch) from the base of the arms. They are subspherical, shortly pedunculated, provided with simple-edged horny rings, largest towards the middle of the arms and gradually diminishing towards the tip, those upon the ventral pair being a trifle smaller than those upon the other arms, and the largest upon the lower lateral pair. Tentacular arms are in length with respect to the sessile arms as 5 to 3. They are compressedly rounded, thickish, equalling in the greatest diameter the basal arms ; they narrow very gradually towards the extremity, with the terminal club scarcely at all widened and occupying just one fifth of the entire length of the arm. Along one side from the base to the end runs a very small membrane. The extremity of the club is much compressed. The hooks are in two alternating series of fourteen each, those of one row being decidedly larger than those of the other, especially the fifth to the tenth hooks, which are very formidable. The cups of the carpal group are ten in number, with about eleven interjacent tubercles, the whole occupying a surface of an elongate-oval form. The cups of the terminal group are thirteen or fourteen in number, and contiguous to one another, and all open, with horny rings. The horny mandibles are black, the upper one considerably the longer, narrower, and more hooked. |