an. Extra protoplasmic Hecretiou of the Polyps ? 163 



" calcareous scales " (Ogilvie). The latter are not calcified calico- 

 blastic "cells" as Ogilvie contended since the calicoblastic ectoderm 

 is now found to be a multinucleated sheet of protoplasm devoid of 

 cell-limits, i.e., a syncytium. 



In fact, there is hardly any evidence to show that the skeleton 

 of the Anthozoa is made up of homologous units just as it is highly 

 doubtful if their soft parts are composed of uninucleated units or 

 cells. The significance of the Anthozoan skeleton would consist in 

 its probable formation within syncytial protoplasm according to 

 physical laws under the presiding activity of the living protoplasm 

 which would direct the complex skeletal architecture. The cal- 

 careous deposit further appears to be differentiated into elements 

 which remain separate as spicules in most Alcyonarians but are 

 united to form a compact skeleton in certain Alcyonarians, e.g., 

 Tuhipora, Corallium, Heliopora, and in all the Madreporaria (in 

 which the calcareous matter may undergo subsequent rearrange- 

 ment). From this point of view, a separate calcareous piece of an 

 Alcyonarian might be regarded as a diminutive corallum, and the 

 corallum of a Madreporarian as a massive spicule, and finally, the 

 formation of the Anthozoan skeleton would be essentially similar 

 to the formation of membrane bone in Vertebrates*. 



References. 



1. Bourne, G. C. " On the Structure and Affinities of Heliopora ccerulea, 

 Pallas. With some observations on the Sti'ucture of A'euia and Hetero 

 xenia." Phil. Trans.., CLXXXVi, p. 455, 1895. 



2. Bourne, G. C. " Studies on the Structure and Formation of the Calca- 

 reous Skeleton of the Anthozoa." Quart. Jour. Micr. Sci., xli, p. 499, 1899. 



3. DuERDEN, J. E. "The Coral Siderastrea radians and its Postlarval 

 Development." Carnegie Institution, No. 20, Washington, U.S.A., 1904. 



4. Fowler, G. H. " The Anatomy of the Madreporaria : I, Flabelhcm, 

 Rhodopsanimia." Quart. Jour. Micr. Sci., xxv, p. 577, 1885; and Stud. 

 Owens Coll., I, p. 243, 1886. 



5. Heider, a. R. von. "Die Gattung Cladocora, Ehrb." Sitzb. Akad. Wis- 

 sensch. Wien, Lxxxiv, p. 634, 1881. 



6. Heider, A. R. von. " Korallenstudien : Astroides calycidaris, Blainv., 

 u. Dendrophyllia ramea, Linn." Arbeit. Zool. Inst. Graz. i, No. 3, p. 153, 

 1886 ; and Zeitsch. Wiss. Zool., XLiv, p. 507, 1886. 



7. Hickson, Sydney J. " The Structure and Relationships of Tuhipora.^ 

 Quart. Jour. Micr. Sci., xxiir, p. 556, 1883. 



8. Koch, G. von. " Ueber die Entwicklung des Kalkskeletes von Asteroides 

 Cali/cularis und dessen morphologischer Bedeutung." Mitth. Stat. Neapel, 

 III, p. 284, 1882. 



9. Ogilvie, Maria M. "Microscopic and Systematic Study of Madreporarian 

 Types of Corals." Phil. Trans., clxxxvii, p. 83, 1896. 



10. Ogilvie, Maria M. "The Lime-forming Layer of the Madreporarian 

 Polyp." Quart. Jour. Micr. Sci., XLix, p. 203, 1906. 



* It is interesting to note that structures analogous to fibrous connective tissue, 

 tendon and bone of Vertebrates, occur in the Madreporaria, viz., the middle lamina 

 ( = mesoglfea), processes of attachment and the calcareous coraUum, a matter which 

 will be discussed in a future communication. 



12—2 



