THE ANATOMY OF THE MADEEPORAEIA. 417 



polyp and those of its parent polyp below, though such a 

 connection might have been expected. The tentacles are 

 apparently both ectoccelic and entoccelic ; but in these, as in 

 other spirit specimens, it is difficult to determine the point 

 with certainty. They are covered with batteries of nematocysts, 

 as in Flabellum (" Anat. Madr.," i., fig. 9) and others. The mouth 

 disc and stomodseum are normal, the lumen of the latter being 

 nearly filled with coils of craspedon or the contorted edge of the 

 mesentery. The mesenteries are generally in twelve to 

 fourteen pairs of normal appearance, and in my specimens bore 

 abundant ova. Unlike the condition recently described in 

 Lophohelia (" Anat. Madr.," iii), there are present two pairs 

 of well-developed "directive" mesenteries; the more remark- 

 able as these two genera are most closely allied, and gemma- 

 tion is of a similar character in both cases. All the mesenteries 

 extend downwards nearly to the parent polyp, but do not 

 touch it. 



The most interesting point in the anatomy of Amphihelia 

 lies in the relation existing between the external body wall and 

 the corallum. For a very short distance round the lip of the 

 calyx are recognisable, as in other free forms previously de- 

 scribed, the characteristic peripheral lamellae of the mesen- 

 teries (fig. 2, a). Just below the lip, however, the coral grows 

 outwards at the points to which these lamella? are attached, 

 and the mesogloea lamina of the body wall comes to lie at 

 these points directly on the broad ridges of coral thus formed 

 (fig. 2, b). A series of canals lined by endoderm is left be- 

 tween these ridges, which are continuous over the lip of the 

 calyx with the ccelenteron. These canals (fig. 3) are, in the 

 main, parallel to the longer axis of the polyp, but are also 

 connected by transverse branches ; they come to lie in about 

 the same radius as the mesenteries, and are generally equal to 

 them in number, but are very irregular, both in position and 

 formation. Like the body wall which bounds them peripherally, 

 they appear to be continuous with the similar canals of the 

 polyps above and below. 



An examination of the corallum shows that the ridges be- 



