100 



CORALS 



young buds are formed, in Turbinaria the primary polyp 

 is suppressed and becomes engulfed in the corallum at a 

 stage such as that shown in Fig. 40. Pace has shown, 

 however, that the primary calyx does persist, but instead 

 of standing up straight from the base it bends to one side 

 and therefore appears in that stage as one of the marginal 

 calices. 



Notwithstanding this peculiar character, and others 

 which have been already mentioned, the general characters 

 of the profusely perforated corallum and the structure of 

 the calices do not justify the removal of the genus from the 

 family Madreporidae in the present state 

 of our knowledge, but our knowledge is 

 still very imperfect, and a detailed study 

 of the structure of the polyps and particu- 

 larly of the method of gemmation might 

 lead to results of importance which would 

 definitely settle the position of the genus 

 in our system. 



Fig. 42. — PyrophyU 



Ua inflata. P"sian PyROPHYLLIA.1— A ^g^US of UUkuOWn 



Gulf, 150 latnoms. o 



X 8 diams. From affinities. A remarkable little solitarv 



fZ'gT' ^^""""'' coral not more than 5 mm. in length b>' 



I mm. in diameter was found in a sample 



of the sea-bottom obtained by Mr. Townsend in the Persian 



Gulf at a depth of 156 fathoms (Fig. 42). 



Its most characteristic feature is that it exhibits almost 

 perfect octo-radial symmetry. There are eight large septa 

 (the protosepta) and eight small ones (the metasepta), 

 never more nor less (Fig. 43). In the centre of the calyx 

 there is an undulating laminate columella. Externally, 

 the thecal wall is marked by from fifteen to twenty annular 

 ridges, which may be considered to indicate a series of 

 intermittent stages of growth, and there are sixteen costal 

 spines and crests on each annulus corresponding with the 



1 S. J. Hickson, Pyoc. Zool. Soc, 191 1. P- 1037. 



