144 THE ANATOMY OF INVERTEBRATED ANIMALS. 



Fig. 30.—Coralli>mi rubrum (after Lacaze-Duthiers ! ). 



I. The end of a branch with A, B. C, three anthozooids in different desrees of ex- 

 pansion ; k, the mouth ; a, that part of the coenosarc which rises into a cup 

 around t lie base of each anthozoOid. 



II. Portion of a branch, the ccenosarc of which has been divided longitudinally and 

 partially removed ; 5, B', B", anthozooids in section; B, anthozooid with ex- 

 panded tentacles; k. mouth ; m. gastric sac ; z, its inferior edge; j, mesenteries. 



B', anthozooid retracted, with the tentacles (d) drawn back into the intermesenteric 

 chamDer-: c, orifices of the cavities of the invaginated tentacles ; e, circum-oral 

 cavity ; b. the part of the body which forms the projecting tube when the antho- 

 zoOid is expanded : a. festooned edges of the cup. 



B'\ anthozooid, showing the transverse sections of the mesenteries. 



-4, A. ccenosarc, wiih its deep longitudinal canals (/), and superficial, irregular, 

 reticulated canals (h). P, the hard axis of the coral, with longitudinal grooves 

 (g) answering: to the longitudinal vessels. 



III., IV. Free ciliated embryos. 



i " Histoire Naturelle clu Corail," 1864. 



