24 Coelenterata. 



coral to open into the chamber occupied by the commensal Aspidosiphon there 

 are from 5 to 9 tubes, the ectoderm of the inner end of which is thickened, 

 vacuolated and contains long piriform gland cells and large granular nemato- 

 cysts with barbs on the thread in a double spiral. The author also describes 

 the anatomy of Heterops. michelini. The tentacles are all endocoelic and there- 

 fore correspond in number to the endosepta, there is a short stomodseum, the 

 ectoderm of the canals leading to the Aspidosiphon chamber loses its glandular 

 character and consists almost exclusively of ciliated columnar cells among which 

 are large nematocysts. The perforate theca of the adult is a network of trabe- 

 culse formed by the peripheral ends of the exo- and endo-septa. In Dendro- 

 phyllia gracilis, the anatomy of which is also described, the ectoderm cells are 

 large and vacuolated and have thick walls which give the layer a semi-carti- 

 laginous consistency. Among these cells are 3 kinds of nematocysts. There 

 are 12 exo- and 24 endo-tentacles. 



Dennant( 1 ) finds, among the living corals of the coast of South Australia 

 and Victoria, examples of the tertiary genus Trematotrochus (In.). This emphasises 

 the close relationship between the living fauna of the Australian seas and the 

 earlier fauna disclosed by the fossils of the tertiary period. Holcotrochus is 

 represented in the collection by 2 sp. (1 n.), one of which is also recorded from 

 the tertiary, and Platytrochus (2) is now recognised as both tertiary and recent 

 in Australia. The author also describes Rhi&otrochus 1 n., Deltocyathus 1 n., 

 Homophyllia 1, Cylicia 1, Plesiastrcea 1 n., Balanophyllia 1 u. 



Duerden( J ) concludes that the two alar fossula} present in certain rugose 

 corals correspond with the region of addition of new septa within the middle 

 two of the 6 primary interseptal spaces, and each is situated on the dorsal 

 aspect of a ventro-lateral or alar septum. The fossula is due to the fact that 

 some of the septa are here shorter and are inclined towards and fused in a 

 successive manner with the dorsal older septa. Alar fossula 1 indicate an in- 

 complete stage in the radial development of septa, similar stages are passed 

 through in the ontogeny of other rugose corals in which the mature calice 

 attains more nearly radial symmetry. The cardinal or ventral-directive fossula, 

 where best developed, is formed by (1) a group of incompletely developed 

 septa (representing a stage in the ontogeny) on each side of the ventral- 

 directive or cardinal septum and (2) a ventral-directive or cardinal septum 

 smaller than the other septa of the first cycle. The smaller cardinal septum 

 was probably correlated with the presence in the rugose polyp of a ventral 

 siphonoglyph in the stomodseum, similar to that which occurs in the living 

 Zoanthese. In the most radially developed species the simple cardinal fossula 

 is represented by only the shortened directive septum. Like modern corals, 

 all the Rugosa exhibit bilateral symmetry during their development and as they 

 approach maturity become more or less radial. The bilaterality and radiality 

 of Tetracorallids and Hexacorallids are of different origin and character, and, 

 along with other characteristics of the two groups, do not imply any relationship 

 beyond the protoseptal stage. 



Gardiner^ 1 ) states that there are great variations in the calicos of Sider- 

 astrcea maldivensis n., according to their position on the colony. He does 

 not accept Doderlein's absorption into Fungia of Cyeloseris and Diaseris. One 

 large specimen of F. dentigera, of which one half of the upper surface, includ- 

 ing the axial fossa, had been killed by silt, shows in 7 places attempted growths 

 of the living edge of the polyp over the sand to reform the mouth and disc. 

 The 65 specimens of this species examined show vegetative variation in contour, 

 height, character of edges, thickness of septa aud spiues of the under surface 



