Zoology.'] NATURAL HISTORY OF VICTORIA. IMoUusca. 



posterior two inches, tapering to posterior end, where sides join to form posterior 

 hollow cone, 6 lines long. A supplementarj' piece of same consistence as pen, and 

 of the same size and shape at anterior end, is attached to anterior end of pen, 

 graduallj' tapering thence to a narrow posterior end at 1 in. 9 Hnes long ; mid-rib 

 and lateral ribs as in pen. Colour: General line of back pale purplish-red from 

 minute chromatophore spots of two sizes ; a narrow, definite, dark-purplish band 

 along middle of whole length of body, a wide triangular patch of same colour on each 

 side of head, the base at edge of eye; and a narrow band of same colour along back 

 of each sessile arm; underside similarly dotted with redder and paler spots; suckers 

 and siphon white. Besides the dots, the whole body gleams with the most beautiful, 

 iridescent, opaline, delicate tints of blue, green, and pink ; the same colours being 

 stronger round the eye, the centre of which is dark-brown. 3Ieasurements : Length 

 from base of sessile arms to posterior tip, 13 ins. Proportional measurements to 

 this, a.s 100 : Width of body at middle, ^^V ; at upper edge of fin, ly,; ; at middle of 

 fin, -Z^; width from lateral angle of one fin to the other, -[^; length of tentacular 

 arms, t^; length of sessile arms, 1st dorsal pair ^-^j^, 2nd pair yV^, 3rd pair -^^ 

 to -^^, 4th or ventral pair -pfoj width of head, ^^; greatest longitudinal extent of 

 fin, yYo; length of body from edge of mantle to posterior end, -y^. 



The present species agrees with the Loligo (Ominastrephes) 

 equipoda of Ruppel in having the sessile arms of two sizes only, 

 hut has larger fins. It nearly resembles the 0. insignis of Gould 

 in shape, hut the relative lengths of the sessile arms distinguish it, 

 as well as the obtuse angles of the fins, &c. I suppose the pen 

 described and figured by Gould for 0. insignis must be imperfect 

 behind and must have lost its generic cone ; also the replacement 

 of the suckers by tubercles on liases of two of the arms in some 

 specimens is, I suppose, accidental. The 0. Sloani (Gray) is stated 

 to have the sessile arms compressed, the third pair acutely finned, 

 with a narrow-rayed membrane on inner edge only of ventral side ; 

 the seventh pair of central series of suckers on tentacular arms 

 largest, in which respect it diifers from the present species. 



The Cuttlefishes forming the genus Ommastrephes are distin- 

 guished from the Loligo., vdih which they were formerly confounded, 

 by the eyes not being covered by skin ; by the lachrymal sinus in 

 upper edge of eyelid ; by the four, instead of six, Ijuccal cavities ; 

 the hollow in head for siphon, and its having four, instead of two, 

 suspenders ; the tentacular arms not being retractile, &c., and the 

 narrow pen with conical cup at posterior end; the want of suckers 

 on buccal membrane ; and the lateral openings on base of siphon. 

 They are all gregarious, inhabiting the mid-ocean, where they form 

 the food of whales, porpoises, albatross, petrels, &c. 



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