MADTIEPOEAEIAN TAMILY — THE rUNGID^. 159 



the basal openings. The canals are less worthy of the name than 

 in the Fungics, because of the occasional discontinuity of the 

 synapticula. 



As might be expected, such a eorallum is a prey to parasitic 

 worms, whose thin soft tubes communicate with the upper sur- 

 face from below, one end being at one of the basal foramina. 



The tubes stain readily, and contain spicules ; and the coral- 

 sfcructure around has been eroded more or less. Also they have 

 produced abnormal growth oE parts of the eorallum in the form of 

 cylindrical cavities which open at the surface in the middle of 

 the tops of septa, giving them a hollow appearance. 



Part V. Summary, 



The examination of species of the genera Fungia, Serpolitha, 

 and Halomitra proves that they are very typical forms of the 

 Fungidae, and that the last genus links these members of the sub- 

 family Funginas on to the more trabeculate kinds. 



The species have a basal wall which is more or less perforated 

 and costulate ; and sections indicate, by means of the micro- 

 scope, that it is composed of the bases of septa united by synap- 

 ticula. The openings, which relate partly to the radial growth 

 of the coral, to the formation of new septa, and to imperfect 

 development of synapticula, are frequently closed during growth. 



The structures of the selerenehyma are septa, synapticula, 

 costse, and a trabecular columella. 



The septa are solid in Serpolitlia, and the larger ones are 

 solid in Fungia, except in the palisade-like septa of Fungia echi- 

 nata ; but in this genus the higher orders of the septa are incom- 

 plete, and irregularly cribriform or fenestrated. This perforate 

 condition does not resemble that of the Madeporaria Perforata ; 

 and it becomes modified with age, solidity often ensuing. In 

 Halomitra a trabeculate and fenestrate condition prevails. 



One of the commonest features of the Fungidae is the union of 

 smaller septa directly with the flanks of neighbouring ones. 

 This occurs in all the species. In Fungia the junction is usually 

 on the flanks, and at the top of the septa as well, and there is a reti- 

 culate enlargement where two small lateral septa unite with one 

 between, and which proceeds to the axis as the conjoined septum. 



In SerpolitJia the larger septa never stretch from the median 

 line to the circumference as in Fungia, but two or three are in a 

 linear series in the radial direction. Under these conditions the 



12* 



