BUB-BRANCHI] > CNIDARIA ANTHOZOA 



~j - ,. 



calcareous spoilers is still illdicat e< 1 1 >y oeea-i< >M;I | del.iehed lri;ictiii-. \Vitll tile 

 clost- of tllr Cretaceous, tin- IMiaivtroiies si-i-ill entirely tu ha\e disappeared. ' 



SuB-Bi;.\.\< H II. Cnidaria. 



The I'niiliiri'i or \< //////ii/*//i/-i/ have a radially symmetrical body. and a 

 terminal niout h-openin^ surrounded by Heshy tentacle-. In tin- ectoderm 

 (.-ometimes also in the entoderm) midoblaM - an- common. from tin- content> 

 of which t lu-r.-nl cells (//>/,/, //V//.s/.<), filled with an nrticatin.u fluid and contaiiiiii- 

 a liolli)\v, spirally coiled thread, arc developed. Kach cnidohlast pOMC 



fine superficial process (en i</<'/l), which is very sensitive to mechanical stimuli. 

 The mesoderm is sometimes entirely absent, but the ectoderm and eiitoderm are 

 >i lonely developed. The ectoderm or mesoderm frequently secrete.- a calcareous 

 or horny skeleton, and both ectoderm and entoderm are eoncerned in the pm- 

 <1 net ion of muscles and nerves. The sexual organs are the product of th' 

 entoderm. 



The Cnidaria are divided into two classes: Autlm-jm and ////'// 



Class 1. ANTHOZOA = ACTINOZOA. Coral Polypi 



I'.imllt/ sessile, cylindrical polyps, possessing a mmith >/////// ////r-/ /"/ ttnl 

 oesophagus, and gastrovascul<n- i-m-lft/. The latter is diri<ll In nun, ma* 

 />"rf it inns (mesenteric folds) into a system of radially dispo&'tl JUHK-IK-*. A cakareotu 

 or }trn >/ tib-lrfon is frequently developed. 



The simple polyp individuals have the form of a cylindrical or conical tithe. 

 at the distal end of which is situated a muscular disk perforate! centrally by 

 the -lit-like or oval fissure of the mouth. The mouth is furnished with a ring 

 of tentacles round its margin, and opens into a membranous oesophageal tube 



1 To the sponges, and iu fact to the Hexactinellids, Hinde lius ivt.-irt-.l the >ingular group 



iiliilne occurring iu the Ordovician, Silurian, and Devonian Systems. Tin--,- an- all free, 



-lolmlar, cup-, or platter-shaped bodies containing a central cavity, and who>e i-alraiv-m.- wall is 



i-i.iupi'.sed nt elements arranged in (jiiinciinxial order. The elements lying on the outer or under 



side of the wall consist of small rhomlioidal plate- having tour transverse rays dispo-i-<l cr. 



and one inwardly directed vertical ra\. '1'he systeinatii- po-iti'Ui of thes,- prol.l.-matical fc-iK 



I ,.f, ,/,/,,!<>, /. Pasceolu*, /*</,,,,/;/,*. /'<,///;/,, /,<,*/>//< i,', ,'/,*) is wholly ,-onje.-tnral ; 



(iiimbel as-, igns them to the calcareous algae (Doctfloporidcte), and others to the Foraniinifi-ia <! 



h monograph l.y A'"/'.//' in AMiamlliingen k. bayer. Akad.-mi,-. II. ('].. Hd. XN'II.. l^l'l'. 



Milne -Edioardf, //., .-t Haimt, ./.. Hist. .ire Naturelle <les Corallaires : :5 vols. an.: 



I'aris. 1857-60, 

 ;/ Edvnrdt, //.. ft //.'//.-, ./.. M.mo^K-iphie des I'olypi. -r- l..>^ih- drs 1,-ii-ain- ].al.-.,/,,i ( |ii.-s. 



Aivh. du .Museum. Pari-. \'M]. \'.. l^.M. 



.l///// -AW/'vov/s. //.. ,-t //,/>',!'. ./., Monograph of the British fossil Coral-. Pala. tl 

 lhnn-,1,1, M.. ibid. ISti'i-tJ'.t. and 1S7'J.- -Me'/ision of the Families and lieiiera of the Srlemdermic 



Zoantharia or Madreporuia. .lourn. Limn-an Sor.. Londmi. Xnni.^y. \-..l. \\"lll.. l s ^i. 

 /',-,1/iii-itfi'l, E. <li'. Introduction a I'l'-lude des IVypiers fos.-iles. I'ari-. 1S58-61. 

 l-'i-iii>'iiti-i, K. ill-, Zoo])hytes. EW^ontologie iVa., raise. Since 1861. 

 A""/"/, /'., Monographic des Polypiers Jura-si. pie.- dr la Sui-se. Abhandl. Sehwei/. pahie..: 



1880-94, vols. VI |. -XX 1 1. 

 K'n'Ii, <'h. ran. Die iinijeschlerhtlirhe N'rrmeliruim dt-r jialai-o/oj-rhen Knrallrn. PalaeontOgraphica, 



Kd. XXIX.. 1883. 



Prat* K., Ueber Septalstructnr. Palaeontographica, 1882. XXIX. 

 Quensttdt, /'. .1.. IVtrela.-tenkun.le DiMits.-hlau.ls. Hand VII., 1889. Rohrcn uinl Sternk..rallen. 



ReU8*, -I. K., Sit/.UllLCsl.rrirhte drl Wirner Akadelnie. 1859, 1864, 1865, 1870 I Dellksrhrif 



VII., XXIII., XXVIIL, XXIX., XXXI.. XXXIII. 



