CEP 



[42] 



C E T 



a approcher d'-un centre. Leu planetes 

 ont une force centripete vers le soleil.) 

 The contrary power to centrifugal, for 

 while the one drives, as it were, the sur- 

 rounding bodies from the centre, the 

 other, the centripetal, attracts and holds 

 them to it. 



CEPHALA'SPIS. A fossil fish of the carbo- 

 niferous series. It has received its name 

 from its head being covered by a sort of 

 shield, having the bones united into one 

 osseous case. In form, this fish bears a 

 resemblance to the elongated trilobites of 

 the transition rocks. Mantell. 



CEPHA'LOPOD. ^ (from K0aX?}, head, 



CEPHALO'PODA. V and TTO^O, feet, Gr.) 



CEPHALO'PODES. J A term applied by Cu- 

 vier to a large family of molluscous ani- 

 mals, from their having the feet placed 

 around their heads, and walking with 

 their heads downwards. The feet are 

 lined internally with ranges of horny 

 cups, or suckers, by which the animal 

 seizes on its prey, and adheres to extra- 

 neous bodies. The mouth, both in form 

 and substance, resembles a parrot's beak, 

 and is surrounded by the feet. It is now 

 well established that the living species of 

 cephalopods which possess no external 

 shell, are protected from their enemies by 

 a peculiar internal provision, consisting 

 of a bladder-shaped sac, containing a black 

 and viscid fluid, or ink, the ejection of 

 which, by rendering the surrounding water 

 opaque, conceals and defends them. The 

 sepia vulgaris and loligo afford us familiar 

 exam pies . Buckland. 



According to Prof. Phillips, the following 

 are the genera of Cephalopoda : Bellero- 

 phon, Orthoceras, Belemnite, Nautilus, 

 Ammonite, Hamite, Scaphite, Baculite, 

 Nummulite. The only living species 

 belong to the genus Nautilus, of which 

 there are two. 



The Cephalopoda, in the arrangement 

 of Cuvier, form the first class of mollusca, 

 aad comprise the following genera, which 

 he divided according to the nature of the 

 shell, Sepia, Nautilus, Belemnites, Am- 

 monites, and Nummulites. 



CERAU'NII LA'PIDES. (from Ktpawbc., 

 Gr.) A name formerly given to fossil 

 echinites, from a supposition that they 

 were formed in the air. 



CERATOPHY'TA. In Linnseus r s arrange- 

 ment, an order, the 6th, of the class Zoo- 

 phytes, or animal plants, comprising 

 Gorgonia, Corallium, Pennatula, &c. 

 They have a horny axis, covered with a 

 fleshy substance, from the cavities of 

 which polypi occasionally appear. 



CEREBE'LLUM. (Lat.) Dim. of cerebrum ; 

 the little brain, situate behind the brain, 

 or cerebrum. 



CF/REBRUM. (Lat.) The brain. 



CE'REBRAL. } (cerebral, Fr. cerebrate, It.) 



CE'REBRINE. S Belonging to the brain ; 

 relating to the brain. 



CE'RITHIUM. A turreted or turriculated 

 univalve, with an oblique opening. La- 

 marck has discovered sixty fossil species 

 of the germs Cerithium in the neighbour- 

 hood of Paris. The recent cerithium i& 

 found at depths varying to seventeen 

 fathoms, and it is stated that so tena- 

 cious of life is at least one species, the 

 cerithium telescopium, that a specimen 

 sent from Calcutta in sea water, lived out 

 of water in a tin-box for more than a 

 week. The recent cerithium has a veil 

 on its head, with two separated tentacula. 



CE'RITHITE. The fossil cerithium. 



CE'RITE. The siliceous oxide of cerium. 



CE'RIUM. A metallic substance discovered 

 by Berzelius and Kissinger in 1804. It 

 was obtained from a mineral called cerite, 

 which was formerly supposed to be an 

 ore of tungsten ; it is also found in allanite. 



CERU'LEAN. ^(cceruleus, Lat.) Blue ; 



CERU'LEOUS. $ sky-coloured. 



CE'RVIX. (Lat.) The neck. 



CERVI'CAL. (cervicalis, Lat. cervical, Fr. 

 cervicale, It.) Belonging to the neck, 

 as the cervical vertebrae, the cervical 

 muscles, the cervical arteries. 



CERVI'COBRANCHIATA. In the concholo- 

 gical system of De Blainville, the name 

 given to an order of shells, comprising 

 the two families Retifera and Branchifera, 

 and the genera Patella, Fissurella, Emar- 

 ginula, and Parmophorus. 



CESTRA'CIONTS. The first and oldest sub- 

 family of sharks. The cestracionts begin 

 with the transition strata, appear in every 

 subsequent formation, and have only one 

 living representative, the Cestracion Phi- 

 lippi, or Port Jackson Shark. The cha- 

 racter of this sub-family of sharks is 

 marked by the presence of large polygonal 

 obtuse enamelled teeth, covering the inte- 

 rior of the mouth with a kind of tesselated 

 pavement. In some species not fewer 

 than sixty of these teeth occupied each 

 jaw. They are rarely found connected 

 together in a fossil state, in consequence 

 of the perishable nature of the cartila- 

 ginous bones to which they are attached. 

 They are found abundantly dispersed 

 throughout all the strata, from the carbo- 

 niferous to the most recent chalk series. 

 Buckland. 



CETA'CEA. Vertebral, warm-blooded ani- 

 mals living in the sea ; they have no gills ; 

 there is an orifice on the top of the head 

 through which they breathe, and eject 

 water ; and they have a flat horizontal 

 tail. The cetacea breathe by means of 

 lungs, and this compels them to rise fre- 

 quently to the surface of the water for 

 the purpose of respiration ; they also 



