CEPHALOPODA. 



517 



datids are bodies endowed with vitality, the 

 most common species of which is the acepha- 

 locyst ; another species is the cysticercus cel- 

 lulosus. The Jilaria medinensis, or guinea- 

 worm, is another parasitic animal which has 

 been seen in the human body. 



Lastly, the cellular tissue may vary in the 

 degree of its consistence, colour, &c. ; and 

 owing to some derangement in the function of 

 nutrition, it may present a preternatural in- 

 crease or a wasting of its substance : (hyper- 

 trophy or atrophy.) 



BIBLIOGRAPHY. Bordeu, Recherches sur le 

 tissu muq., in his works by Richerand. W. Hunter, 

 in Med. Obs. and Inq. vol. ii. p. 17. Holler, 

 Elementa Physiolog. The systems of Portal, 

 Bichat, Meckel, Beclard, Craigie, and ^Grainger, 

 Blandin Sf Beclard, Add. a 1'Anat. Gen. de Bichat. 

 Diet, de Med. art. Cell. Tissue. M. Edwards, 

 Recherches microsc. sur la struct, intime des tiss. 

 organ, des anim. Hodgkin, Annals of Phil. Aug. 

 1827. The systems of physiology by Blumenbach, 

 Ttfajendie, Bostock, and Tiedemann. Fodera, Journ. 

 de Phys. t. iii. p. 35. Lindley, Introd. to botany. 

 Roget, in Bridgwater Treat., Anim. and Veget. 

 Phys. Grant's Lectures, Lancet, 1833, 34, vol. ii. 

 p. 257. De Blainville, De 1'organis. des animaux. 

 Hunter, Treatise on the blood, &c. Thomson's 

 Lectures on inflammation. James, Observations 

 on inflammation. Portal, Cours d'anat. med. t. ii. 

 t. v. Lairrence, Lectures on inflammation, in Lancet, 

 vol. i. 1829, 30. Hastings, Treatise on the lungs, 

 p. 57. Billard, Traite des mal. des enf. nouv.-nes, 

 p. 169. Gendrin, Hist. anat. des inflam. t. i. p. 14; 

 t. ii. 358. Andral, Precis d'anat. pathol. Otto, Com- 

 pendium of pathological anatomy, by South. Cop- 

 land, Diet, of Pract. Med. art. Cellular Tissue. Wells, 

 Transactions of a Society for Improvement of Medi- 

 cal and Chirurgical Knowledge, vol. iii. Brescliet, 

 Recher. sur les hydrop. actives, &c. Paris, 1812. 

 Blachall, Obs. on dropsy, London, 1813. Aber- 

 crombie, in Edin. Med. and Sur. Journal, vol. xiv. 

 Ayre's Researches into the nature and treatment of 

 dropsy, p. 1 et seq. Cyclop, of Pract. Med. art. 

 Anasarca. Diet, de Med. et de Chir. Prat. art. 

 Acephalocystes, Anasarqiie, Emphyseme, Entozoaires, 

 Injiamination. Mayo, Outlines of human patho- 

 logy. Lobstein, Traite d'anat. pathol. p. 201. 

 Duncan, in Trans, of Med. Chir. Soc. Edin. vol. i. 



( R. D. Grainger.) 



CEPHALOPODA (xitpa^, caput, 

 pes); Eng. Cephalopods ; Fr. Ccphalopodes ; 

 Germ.Kopffusslern, Blackfische, Tmten-fsche; 

 Ital. Seppie, Polpi. Syn. MaX>ci, Aristotle; 

 Mollia, Pliny; the genera Nautilus, Argo- 

 nauta, and Sepia, Linne ; Octopodia, Schneider; 

 Mollusca brachiata, Poli ; Mollusca Cephalo- 

 poda, Cuvier ; Cephalopoda, Lamarck, Leach ; 

 Brachiocep/iala, Cephalophores, De Blainville ; 

 Pterygia, Latreille, (including the Pteropoda 

 of Cuvier); Antliobrachionophora, Gray. 



Definition. A class of Molluscous Inver- 

 tebrate animals in which the head (A, figs. 

 206, 209,) is situated between the trunk (B) 

 and the feet (C), or principal organs of loco- 

 motion. 



Characters of the Class. The trunk or body 

 is thick and soft; varying in form from a 

 sphere, to a flattened ellipse, or elongated 

 cylinder; sometimes protected by a shell, 

 sometimes naked; consisting of a membranous 

 or muscular sheath or mantle, with a transverse 



anterior* aperture (a, figs. 206, e t seq.) and 

 containing the respiratory, circulating, gene- 

 rative, and principal digestive viscera : the 

 mantle sometimes supports a pair of fins (b, 

 fgs. 207, 208, 209,) and, in the naked species, 

 lodges in its substance the rudiments of a shell. 



The head is distinct from the trunk, of large 

 size, and of a rounded figure ; it contains the 

 organs of sense, mastication, and deglutition, and 

 gives off from its anterior circumference or exter- 

 nal surface, a number of fleshy processes which 

 encircle and more or less conceal the mouth. 



These processes, by some naturalists termed 

 the feet, but which we prefer to call, with Poli, 

 the arms, are either very numerous, short, and 

 hollow, containing each a long, slender retrac- 

 tile tentacle (fgs. 205, 213) ; or they are eight 

 (fgs. 206, 210), or ten (fgs. 207, 208), 

 in number, solid, supporting on their internal 

 surface numerous suckers (antlia, acetabula) ; 

 and being more or less elongated and flexible in 

 every direction, they act as powerful organs of 

 adhesion, prehension, and locomotion. 



The eyes are a single pair, of large size, 

 varying in relative perfection of structure ac- 

 cording to the locomotive powers of the spe- 

 cies, and either pedunculated or sessile. 



The mouth is anterior, and situated at the 

 bottom of the conical cavity formed by the 

 base of the feet ; it is provided with two horny 

 or calcareous jaws, shaped like the mandibles 

 of a Parrot, playing vertically on each other, 

 and inclosing a large fleshy tongue, which is 

 armed with recurved horny spines. 



The branchuE are concealed within the man- 

 tle, and are symmetrical in size, form, and posi- 

 tion. The systemic circulation is aided by a 

 muscular ventricle. 



The infundibulitm, (i,fgs. 206, 208,) or pas- 

 sage through which the respiratory currents and 

 the excrements are discharged, is a muscular 

 tube, situated at the anterior part of the neck, 

 shaped like an inverted funnel, with the pipe 

 projecting from the visceral cavity, and directed 

 forwards. 



The sexual organs are separate and exist in 

 distinct individuals ; but whether impregnation 

 takes place by copulation or after the ova are 

 excluded is not determined; the former is most 

 probable. 



All the species are aquatic and marine. 



Division of the Class into Orders. The 

 type of organization which characterizes the 

 Cephalopods, and of which the preceding is a 

 general outline, presents two principal modi- 

 fications, according to which the class is di- 

 vided into two orders. t 



' Throughout the present article the terms of 

 aspect and position relate to that in which the 

 animal is represented in y?*/. 206. The shell covers 

 the posterior part of the body, the arms are anterior 

 and directed forwards; the letters A, B, C, are 

 along the dorsal or upper surface, the letter t is 

 beneath the ventral or lower surface. 



t A third order of Cephalopods (the CelMacea 

 of De Blainville) has been proposed to include an 

 extensive series of minute polythalamous shells, of 

 exquisite beauty in their form and sculpture, which 

 differ from the camerated shells of our Tetrabran- 

 chiate order in the absence of a siphon, but which 



