A. F. Verrill — Comparisons of Coral Faunae. 177 



Oculina coronalis Quelch. 



Voy. Challenger, xvi, p. 49, pi. i, tigs. 6-6c. 



Ivory Coral. 



This is an openly branched arborescent species, with the branches 

 long, often divaricate and contorted, spreading in all directions, 

 seldom coalescent. 



The most important character is the corona-like, close group of 

 12 erect, stout pali, which seem to be rather more developed than is 

 usual in any of the other species. The columella is well developed, 

 papillose. Septa 24, unequal, very granulated, little exsert. Calicles 

 distant, 2 to 3 mm in diameter. 



I have seen no specimens agreeing perfectly with this form, which 

 may be a distinct species. But in most respects it agrees pretty 

 closely with some specimens of 0. pollens, from which it may not be 

 distinct. 



Family Mussidae. See p. 115. 

 Mussa Oken, Dana. See pp. 115-118, 128. 



\fussa + Symphyllia + Isophyllia + Mycetophyllia + ? Ulophyllia Edw. & 

 Haime, Hist. Corall., ii, 1857. 



Cactus Corals. 



Since printing the previous article, I have had occasion to study a 

 new species of Mussa, described below, which is closely related, in 

 most respects, to the typical species of Isophyllia, but yet it has the 

 larger, exsert, distal septal teeth and the distally thickened septa 

 characteristic of 3Iussa. See fig. 12. 



In fact, it is truly intermediate between the two groups. 



Consequently I am now led to reunite them, together with Sym- 

 phyllia, Mycetophyllia, and Ulophyllia, in the old genus Mussa. 

 But it may, nevertheless, be convenient to keep them in use as sub- 

 ordinate groups, equivalent to sub-genera, or sections, that are not 

 clearly limited by structural characters, such as should characterize 

 true genera. 



On pages 115, 116 (note) I have already stated that this would 

 probably have to be done eventually. See also my remarks, below, 

 on the Brazilian species (31. tenuisepta and M. liraziliensis), which 

 are also connecting species. 



It is easy, also, to find in some calicles of typical Isophylliai, like 

 I. fragilis, septa that have the distal teeth larger than the rest. 



Trans. Conn. Acad., Vol. XI. 12 December, 1901. 



