THE ANTHOZOA PERFOEATA OF GOTLAND. 9 



D'Orb. and especially Actinofungia Fromentel, which, as may be seen in the work of this 

 author (Introd. ä letude des ép. foss. Pl. IV fig. 8), is provided with radiate oscula clo- 

 sely resembling those of the Silurian Coenostroma, and inoreover with a coenenchyma as that 

 species. But most of thetn must without doubt be considered as sponges as they consist 

 entirely of silica, and, wbat is decisive, have the spicula? of the true Spongias. The calice 

 of the Montiporina? indeed indieates a coral of a very low type, where the septal appa- 

 ratus, the most distinctive part of the Anthozoa is so feebly developed as to be confoun- 

 ded with the openings or oscula (»oscules étoilés» Fromentel) seen in so many Spongise. 

 A large, compound, siliceous Silurian sponge of a genus not yet described shows on its 

 protuberances almost the same stellate rays as so many of the Montiporinae. On the other 

 side what most decidedly militates against the Coenostroma being considered a sponge is 

 the very characteristic tissue of its coenenchyma, developed as in the Poritidaä. that it 

 consists chiefly of carbonate of lime and is totally devoid of anything that might be con- 

 sidered as spongian spicula?. As far as I am aware from the recent researches of Prof. 

 £Leckel on the calcaraous Spongiae *) not a single species of these numerous low structu- 

 red animals is provided with anything but few and scattered and loosely connected spi- 

 culas, which have a decided spongian character, and no species is in possession of a scle- 

 renchj-ma coherent in a rnass, so -as to resemble a polyparium when the soft tissues of 

 the animals have disappeared. It may nevertheless be that several amongst the Montipori- 

 na3 show a great spongian affmity, such as one now might not be unprepared to find 

 amongst the Anthozoa, since the researches of Hackel and Miklucho have shown antho- 

 zoan affinities amongst several Spongiae. 



The idea of the spongian affinities of Coenostroma was already foreshadowed by 

 Goldfuss who (Petref. Gerin. Vol. I p. 215) says that the Stromatoporaä are »schwamrn- 

 artige Zoophyten». Blainville also (Diet, Sci. Nat. Vol. 60 p. 378) doubted whether it were 

 a true coral or a fragment of a Spherulites. Lastly M. Fromentel (Introduction ä letude 

 des éponges fossiles p. 37) has placed the Devonian species of Coenostroma amongst his 

 »Spongitaria osculata» in the new genus Sparsispongia. 



Coenostroma discoideum was first described by Mr Lonsdale in Sir Rod. Murchi- 

 son's Silurian System (Vol. II p. 688 pl. 16 fig. 1) with the name of Porites discoidea, but 



N. Cor. III, p. 225) and the very characteristic sclerenchyma of all the Perforate Corals. On the other 

 hand the Eecent Tabulata of the genera Pocillopora, Seriatopora and Heliopora have a compact, not tra- 

 becular sclerenchyma, quite as the fossil Tabulata, and there is a distinct wall around their calice. Mille- 

 pora does not show the least affmity to the other genera which are ranged amongst the Milleporidse. Its 

 calices are entirely void of a wall and consist only of tubular perforations in the spongious tissue. They 

 are moreover very irregularly and indistinctly septate, what does not obtain in the Palseozoic and other 

 Tabulata. I theri think that Millepora had to he placed rather amongst the Perforate, than amongst the 

 Tabulate Corals. Its being provided with tabute is no conclusive evidence as to its affinity to the Tabu- 

 lata, as there are several true Eugosa (Columnaria, Cystiphyllum, Pholidophyllum etc.) with well developed 

 tabulee and the septa much reduced. Thence all conclusions that may be derived from the polyps of 

 Millepora ought not to be applied to the fossil Tabulata, the true living representatives of these being, in 

 my opinion, Pocillopora and Seriatopora, the polyps of which are still unknown. — The genus Axopora 

 (formerly Holartea) Edw. & H. seems also to share the peculiarities of Millepora. 



') PLeckel, Ueber den Organismus der Schwämme, Jenaische Zeitschr. fur Medicin und Naturwissenschaft 

 5:r Bd. p. 207. 



K. Vet. Akacl. Handl B. 9. N:o 6. - 



