Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/771

Rh healtb of the grinding trade ; and the more general use of the fan in dry grinding has considerably reduced the excessive mortality among the operatives.  CUTTACK. See.  CUTTLE-FISH. The cuttle-fishes are the &quot;Dinten- fische &quot; of the Germans and the &quot; Seiches &quot; of the French, and they constitute the most highly organized members of the class of the Cephalopoda. The great class of animals now known to naturalists under the name of Cephalopoda was fully recognized by Aristotle as a well-marked division of animals, under the name of Malakia. Even at the early period at which he lived (–), this acute observer recognized at least nine species of Cephalopods including the Argonaut and the Pearly Nautilus ; and he also recorded the singular phenomena of reproduction, phenomena which were not scientifically confirmed and fully established till the year 1850, by the researches of Verany and H. Miiller. The other classical writers (e.g., Pliny) added nothing to Aristotle s observations. The next contribution of import ance to the elucidation of the history of the Cephalopods was made by Puimph (1705) in his Rariteit-Kamer, describing the curiosities of Amboyna. The old Dutch naturalist gives in this work an account of the structure and habits of the Pearly Nautilus, which, though long dis credited, is now known to be in the main correct, and which is accompanied by a fair figure of the soft parts of the animal. The relations of various fossil forms (such as Ammonites) to the Cephalopoda were first recognized in the earlier portion of the 18th century; and Breynius (1732) detected the true affinities of the Belemnite. Lin naeus gives a summary of the knowledge of his time as to these animals, but separates the naked from the testaceous forms. The first establishment of the class Cephalopoda, however, as a definite natural group, is due to the genius of Cuvier (1798), to which we also owe this now universally accepted name. Cuvier s researches on this subject are contained in his Lemons d Anat. Comparee (1799-1805), and were subsequently republished in an enlarged form in his Memoir e sur les Cephalopodes et leur Anatomic (1817). Since the appearance of this classical work, our knowledge of the natural history of the Cephalopods has been immensely increased by the researches of Delle Chiaje, Meckel, Von Siebold, De Blaiuville, Owen, Van Beneden, Peters, Van der Hoeven, Gray, Huxley, A. Hancock, Milne- Edwards, Kolliker, H. Miiller, Leuckart, Steenstrup, Keferstein, Ferussac, D Orbigny, &c. ; and, as regards fossil forms, by Buckland, D Orbigny, Queustedt, Oppel, Owen, Huxley, Phillips, Von Buch, Miinster, Barrande, Von Hauer, Von Meyer, Hyatt, Hall, Meek, and many other palaeontologists. One of the principal steps in advance upon the knowledge possessed by Cuvier was taken in 1835, when Dujardin showed that the Foraminifera, previously included by Plancus, Soldani, Fichtel, Linnaeus, and others in the Cephalopoda, were in reality of a much lower grade of organization, and were not systematically related to the true Mollusca. The class Cephalopoda comprises Mollusca in which there is a distinct head, and a toothed &quot;tongue&quot; or &quot; odontophore,&quot; whilst the hinder extremity of the body is inclosed in a muscular mantle-sac, which may or may not secrete an external shell. The mouth is placed near the centre of the &quot; foot,&quot; and the margins of this structure are split up into 8 (Octopod Cuttle-fishes), 10 (Decapoc Cuttle-fishes), or numerous (Pearly Nautilus) muscular pro cesses, or &quot; arms.&quot; The lateral margins of the foo (&quot; epipodia &quot;) constitute, by apposition or fusion, a muscular tube (the &quot; funnel &quot;) through which the effete water o: respiration is expelled. The class Cephalopoda is divided into the two grea orders of the Tetrabranchiata and the Dibranchiata. {{ti|1em|The Tetrabranchiate order comprises only the living pecies, or varieties, of the Pearly Nautilus (Nautilus pom- nlius}, along with a vast number of fossil forms, and is characterized by the possession of an external, many-cham- &amp;gt;ered, siphunculate shell ; by the presence of numerous irms, which are devoid of suckers ; by the possession of our branchiae ; by the absence of an ink-sac ; and by the act that the " funnel " does not form a complete tube.}} The order Dibranchiata, with which alone we are con cerned here, comprises the true cuttle-fishes, in which there are either 8 or 10 arms, provided with suctorial discs ; .here is no external shell, or, in the single case in which such a structure is present (the female Argonaut), it s single-chambered, and is not secreted by the mantle there are only two branchiae ; an ink-sac is present ; the &quot; funnel &quot; forms a complete tube.

FIG. 1. A. Loltff } MiJgaris ; a, arms ; t, tentacles. B, pen of the same reduced In size C, side-view of one of the suckers, showing the horny hooks surrounding the margin; D, view of the head from in front, showing the arms (a), the tentacles (t), the mouth (m), and the funnel (/).

{{ti|1em|The body of a cuttle-fish is symmetrical, and is divisible into an anterior cephalic portion (prosoma} and a posterior abdominal portion (mctasoma). The former of these _ is developed into a distinct head, furnished on its sides with large and prominent eyes, and having the mouth in the centre of its anterior surface, surrounded by eight or ten " arm-s." The latter incloses the various viscera, and is en veloped in an integumentary sac, which corresponds to the " mantle " (" pallium ") of the Gasteropoda and Lamelli- branchs. The mantle-sac is formed by the coalescence of the two pallia] lobes along the ventral surface of the body, and it is attached directly to the metasoma along the dorsal surface, whilst it is free inferiorly, and incloses a space (the " pallial chamber ") which contains the gills, and into which the intestine and the ducts of the generative organs and ink-sac open.}} The integument of the cuttle-fishes consists of several layers, of which the most . important is one which corresponds to the lowermost layer of the epidermis, and which 