EEPORT ON THE ACTINIARIA. 107 



.also partly invaginated and retracted into the radial chambers in a way which is more 

 common among the Octocorallia than among the Hexacorallia ; in this case the sequence of 

 the layers is inverted in transverse sections, as the ectoderm is turned inwards, the endo- 

 derm outwards. There arc fourteen tentacles in all, each of them belonging to a radial 

 chamber. 



On the oesophagus there are alternately eight longitudinal furrows and eight longi- 

 tudinal thickenings (PI. XIII. fig. 3), but little can be said about their constitution, as it 

 was plainly very much influenced by the contraction of the body. The deepest furrow 

 belongs to the interspace between the two directive septa, and may be regarded as an 

 oesophageal groove, even though I was not able to make out distinctly that it is covered by 

 a specially constituted epithelium. The transverse section of the oesophagus is roundish, 

 so that the flattening in the direction of the transverse axis, common to many Actiniae, 

 is wanting. 



The septa are perfect without exception. They are thin lamellae bearing a very strong 

 muscular pennon, in the middle between the oesophagus and the wall. At this point the 

 longitudinal muscles are pleated in a sharply defined space nearly as thickly as in Tealia 

 bunodiformis ; besides these, a special cord of longitudinal muscles runs along the wall and 

 a rudimentary parietobasilar muscle lies in a similar position on the side of the transverse 

 muscles. A wide marginal stoma can be seen in transverse section between the two 

 longitudinal muscular cords. 



The arrangement of the septa and the nature of the reproductive organs is of the highest 

 importance. Scytophorus striatus is the only Actinia known at present, in which the 

 number of the pairs of septa is unequal. This is not an accidental abnormality, as it is 

 caused by the absence of the second pair of directive septa and not by irregular growth of 

 the different parts of the body; this was clear from both the specimens under examination 

 as in each one wall was furnished with fourteen longitudinal furrows, corresponding exactly 

 to the fourteen septa, i.e., to the seven pairs. The existing pair of directive septa is only 

 distinguished from the other septa by the lamellae being shorter, on which account the wall 

 and the oesophagus approach nearest to one another at this point. 



Scytophorus striatus belongs to the small number of Actiniae in which herma- 

 phroditism has been undeniably observed ; all the septa (the directive septa included) 

 bear ova in their upper sections, many of which were almost mature in the specimen 

 I examined, whilst the lower sections bear testes, though these were not so numerous as 

 the ovicells. 



Tribe IV. Edwaedsle. 



Actiniaria with eight septa ; among which are two pairs of directive septa, whilst the 

 remaining four septa are not paired ; all the septa furnished with reproductive organs ; 

 tentacles simple, usually more numerous than the septa. 



