Dr. F. Briiggemann on Stony Corals. 311 



Ilomophyllta australis. . Types, B.M. 



Caryophyllia amtralis, M.-Edw. & Haime, Ami. Sc. Nat. (3) Zool. x. 

 p. ,3:^0, pi. 8. fig. 2; iid. op. cit. xi. p. 239. 



In this species the septa are moderately prominent, rather 

 thin, of uniform thickness throughout their whole length, and 

 delicately scabrous from the presence of numerous very small 

 pointed granules. The septal systems are quite distinct. 

 There are six cycles, the last of which is incomplete. The 

 primary and secondary sej^ta are equal j the teeth of their 

 edges are much crowded, middle-sized, narrow, straight, rather 

 obtuse ; those in the middle part of the septal edge are, on the 

 average, the longest ; they decrease in length towards the 

 circumference and centre of the calicle. The tertiary septa 

 are much like tiie preceding, only a trifle narrower, with fewer 

 and longer teeth ; those of the fourth cycle are similar, but 

 they do not reach the columella. Tlie septa of the fifth and 

 sixth cycles are only half as long as those of the fourth, and 

 scarcely dentate on their edges. The columella is much re- 

 duced and low, its surface subpapillose. 



Very young specimens (4 to 8 millims. in diameter) are 

 broadly attached and very short cylindrical, almost discoid. 

 The epitheca is present from the beginning. 



Height of the adult 20 millims. ; diameter of calicle as 

 much as 30 millims. 



Hah. Port Lincoln [J. B. Harvey in B.M.). The state- 

 ment " Chinese seas " {M.-Edw. & H. 1857) is doubtful, and 

 requires confirmation. 



Milne-Edwards and Haime, in their later works, have mis- 

 taken this coral for the young of a West-Indian Isophyllia\ 

 the description oi IsojjhylUa " australis " (Hist. Nat. Cor. ii. 

 p. 375) has nothing to do with the species now under consi- 

 deration. The latter is found growing socially on rocks ; and 

 occasionally it happens that two neighbouring specimens 

 touching each other become intimately united by their walls. 

 Sucli is the case in one of the type specimens; and it is most 

 likely that from the observation of this spurious compound- 

 ness (which is only caused by contact, not by fissiparity) 

 Milne-Edwards and Haime arrived at their erroneous conclu- 

 sion. There can be no doubt that Homophyllia remains 

 solitary at all ages. The young IsophyUio;^ moreover, are 

 quite different : they are expanded, convex, with flat under 

 surface and lamelliform costaj ; they divide in a curious 

 manner, according to the septal systems. E. de Pourtalfes 

 first noticed this kind of development in his /. guadulpe.nsis 



22* 



