ANATOMY OF THE MADREPORARTAN CORAL FQNGIA. 301 



There ai'e twelve pairs of septa of the third order. Each 

 pair of this order embraces a septum of the first order. The 

 fourth order contains twenty-four pairs of septa, each pair 

 embracing alternately a septum of the first and a septum of 

 the second order. 



The fifth and sixth orders also contain twenty-four pairs of 

 septa each. Those of the fifth order are the longer, and each 

 pair embraces a septum of the first and second orders alter- 

 nately; those of the sixth order are much shorter, and each 

 pair embraces a septum of the third order. 



These last two orders, the fifth and sixth, very possibly 

 represent only one complete cycle of septa and tentacles. But 

 since the difference in the length of the septa shows a differ- 

 ence in their time of origin I have thought it better to keep 

 them separate. 



The seventh order contains ninety-six pairs of septa, with 

 their corresponding tentacles. The septa are extremely short 

 and rudimentary ; the tentacles are minute and placed close to 

 the circumference of the disc. 



The sequence of the septa is 1, 7, 5, 7, 4, 7, 6, 7, 3, 7, 6, 7, 

 4, 7, 5, 7, 2, 7, 5, 7, 4, 7, 6, 7, 3, 7, 6, 7, 4, 7, 5, 7, 1, in each 

 system. 



The tentacles are arranged in six tolerably definite circles at 

 different distances from the mouth, as may be seen in figs. 1 

 and 2. The arrangement both of tentacles and septa is very 

 regular and easily made out at each end of the long axis of the 

 mouth, but it becomes more irregular and obscure at the sides. 

 Thus, contrary to previous statements, Fungia is perfectly 

 regular, and agrees with other Madreporaria in the arrange- 

 ment of tentacles and septa. The tentacles, which are small 

 and club shaped in most species, are correctly figured by 

 Dana. The remaining external features do not call for special 

 notice and may be understood by reference to fig. 1. 



To examine the internal structure, I decalcified some speci- 

 mens in nitric acid solution, and afterwards stained and cut 

 sections from them in the usual way. Another specimen I 

 half decalcified and dissected, and further made use of the 



