7. Anthozoa (incl. Hydrocorallia). B. Alcyonaria. 27 



at the surface of the colony, were composed of a horny substance in which 

 a few long spicules of calcium carbonate were imbedded. In the lower and 

 older parts of the colony the horny substance became impregnated with calcium 

 carbonate, and finally, at the base, nearly the whole of the organic substance 

 became replaced by the inorganic salt. The cor a Hum is apparently similar in 

 construction to that of Heliopora, and is probably formed by crystallisation of 

 calcium carbonate in an organic matrix. There are vertical trabeculse from 

 which the crystalline rods diverge in three directions, meeting in sutural junc- 

 tions with similar diverging systems. There are no dark lines or centres of 

 calcification such as occur in the Madreporaria. C. is referred to the Cosno- 

 thecalia; it differs from H. in the monomorphic condition of the pores, the 

 absence of tabuke, the complete closure of the tubes below by the continuous 

 growth in thickness of the thecal walls, and in the presence of spicules. In 

 this last character C. may be regarded as intermediate between the Cceno- 

 thecalia and the Stolonifera. The new family Ceratoporidse is thus defined: 

 Coenothecalia forming a massive skeleton of crystalline calcium carbonate, in 

 which a few slender spicules are imbedded; no tabulae, the tubes closing below 

 by the continuous growth of the thecal walls; pores monomorphic and small 

 (in the type species 0,2 mm. in diameter). 



Neumann gives an account of his researches on the axes of Pterogorgia 

 pinnata, Gorgonia sp., Lophogorgia alba and sp., Plexaura flavida and Plexaur- 

 ella dichotoma. He concludes that the axis of Plexaurids and Gorgonids is 

 not a secretion product of an ectodermal axis-epithelium, but is of mesoglceal 

 origin. Numerous spicules, of undoubted mesogloeal origin, are imbedded in 

 the outer horny layers of many axes. An axis-epithelium is present in many 

 cases (though absent in PI. /".), but it arises from the mesoglcea. The central 

 strand of the axis in each lateral branch is formed independently, and is 

 separated from the principal axis by a horny layer. In Pt. p. and G. the central 

 strand in the axis of a lateral branch widens as it approaches the principal 

 axis, gradually pushing away the mesogloea and so joining the principal axis. 

 In PL /"., in the horny outer layer of the axis, and in the zone between this 

 and the central cord of the axis, there are cells belonging to the mesogloea, 

 which become more and more cornified and thus furnish the horny substance 

 of the axis. In Octocorallia generally the skeleton has a mesoglo3al origin, 

 while in the Hexacorallia it is formed by the ectoderm. Koch's view, that 

 the Scleraxonia are distinct from the Gorgonacea, cannot be accepted. 



Nutting describes the Scleraxonia collected by the Siboga, namely, 

 Solenocaulon 4 (2 n.), Titanidium 1 n., Semperina 2 (1 n.), Suberia 3 (2 n.), 

 Paragorgia 1, Iciligorgia 1, Suberogorgia 1 (3 n.), Keroeides 1, Melitodes 6 (2 n.), 

 Acabaria 5 (3 n.), Hopseida 3 (2 n.), Wrightella 2, Parisis 2, and Birotulata n. (1 n.) 

 which bears a close superficial resemblance to Melitodes ochracea, but the spicu- 

 lation of the two colonies is so different as to justify their generic distinction. 



Thomson & Mackinnon describe 35 species (13 n.) of Alcyonaria collected 

 by the Thetis in Australian waters. They comment on the frequent occur- 

 rence of encrusting colonies of Alcyonium membranaceum and reptans, which 

 grow over Gorgonid axes in a very misleading manner. The species recorded 

 are Clavularia 1, Alcyonium 3 (1 n.), Lithophytum 1, Dendronephthya 1 n., 

 Mopsella 2, Psilacabaria 1, Parisis 1, Mopsea 6 (4 n.), Acanthoisis 1, Stachy- 

 odes 1, Amphilaphis 1 n., Plumarella 5 n., Primnoella 3, Caligorgia 1 n., Lepto- 

 gorgia 1, Ctenocella 1, Telesto 2, Kophobelemnon 1, Godeffroyia 1, Sarcophyllum 1. 



Thomson f 1 ) gives an account of the following Alcyonacea from the Cape of 

 Good Hope and Natal Bellonella 2 (1 n.), Metalcyonium 3 (1 n.), Alcyo- 



Zool. Jahresbericht. 1911. Coelenterata. o- 



