OCR Text |
Show 24 ZOOLOGICAL COLLECTIONS M A D E DURING [Jan. 4, by the peculiarity of one of the arms possessing a double set suckers. LOLIGO PATAGONICA, sp. n. (Plate III. figs. 2-2 d.) Body cylindrical, tapering gradually behind, about four times as long as broad. Upper margin produced to an acute point on the dorsal side, broadly sinuated beneath. Fins occupying a little less than half the length of the body, rhomboidal, with the lateral angles only slightly rounded, joining the body without any superior slit. Head a little narrower than the body. Of the arms the upper or dorsal pair are the smallest and shortest, with an acute membranous inner edge. Second pair rather longer and thicker, having the inner or upper edge more rounded than the outer, which is acutely carinate. Third or lower lateral pair largest and longest of all, rounded on the upperside, and bearing a broad membranous expansion on the lower edge extending from the tip to the base, where it joins a similar membrane running up the side of the basal arms. These are nearly as thick as the preceding but rather shorter, and have a very acute carinated inner edge. Cupules on the upper and lower pairs rather smaller than those on the lateral pairs. Horny rings very oblique, furnished on one side with five or six rather squarely cut teeth. Buccal membrane produced into seven prominent lobes, whereof the two subbasal pair are the most conspicuous, within bearing a few minute suckers upon very long pedicles. Tentacular arms slender, tapering at the ends. Club but little expanded, furnished with four rows of cups, whereof the two inner are vastly larger than the outer; they alternate with each other and also with the small outer cups, so that the latter on one side are on the same transverse line as the more remote series of large oues. The length of the club is about five twelfths of the entire length of the tentacle. The horny ring has about from twenty to twenty-four blunt teeth. The colour of the two specimens is purplish buff, varied with numerous close-set, generally ovate, largish spots of a purple tint, and of different sizes, upon the back, the sides, and crown of the head. Ventral surface and beneath the fins destitute of spotting. Shell pennate ; shaft thin, roundly keeled exteriorly and grooved on the opposite side; expanded portion or vane rather broad, equalling in this respect rather less than one sixth of the length. Dimensions. Length of body 62 millims., width 14; fins 27 long and 30 in diameter across the back from one lateral angle to the other ; tentacles 38 long; longest arm 27. Hab. Alert Harbour, Trinidad Channel, west coast of Patagonia. Only one species of this genus has been hitherto recorded from the west coast of the South-American continent, namely Loligo gahi, found on the Chilian coast. In that species the fins are considerably shorter in proportion to the length of the body, join the back nearer the centre, and have rounded upper and lateral angles. The amis, too, offer certain differences; and the number of teeth on the horny rings of the larger cups on the tentacular club is |