ABYLA HAECKELI. 223 



would be a needless repetition. The one important point of difference is the 

 nature of the ventral facet, whether simple and with concave lateral margins 

 (.4. trigona), or divided into a lower pentagonal and an upper rectangular por- 

 tion by a well-marked transverse ridge (.4. haeckeli). The upper lateral facet 

 is likewise proportionately larger in haeckeli than it is in trigona (compare fig. 1 

 with fig. 3, Plate 13). 



The posterior nectophore of .4. haeckeli is so far known only from Huxley's 

 description and figure ('59, pi. 3, fig. 1), from which it is clear that it closely 

 resembles the corresponding structure in .4. trigona. Without a study of actual 

 specimens of haeckeli it is impossible to state whether or not the posterior necto- 

 phores of the two species show any constant differences in form or structure. 



EuDOXiD. Neither the "Siboga" nor the "Albatross" material throws 

 any light on the Eudoxid of A. haeckeli. Huxley described and figured a bract, 

 which, though detached, was taken together with his one specimen of A. haeckeli, 

 as resembling the Eudoxid of A. trigona (" Amphiroa alata") except that the 

 basoventral margin of the hydroecium is deeply concave, instead of being 

 straight. And it is just this character which distinguished his Amphiroa angu- 

 lata (taken once only), which he thought might prove to be a young stage of 

 the Eudoxid of A. trigona. Recently Bedot ('96) has described, from Amboina, 

 an "Amphiroa" which likewise has a deeply concave ventrobasal hydroecial 

 margin, besides having asymmetrical lateral hydroecial walls with a prominent 

 basal tooth on the right, and none on the left side, under the name Amphiroa 

 dispar. On comparing Huxley's figure ('59, pi. 5, fig. 2) of angulata with the 

 lateral view of dispar given by Bedot ('96, pi. 12, fig. 6) we see that angulata, 

 like the latter, has a prominent basal tooth on the side of the hydroecium. And 

 this, together with the concavity of the basoventral hydroecial margin present 

 in both, and their generally close agreement in other respects, is sufficient ground 

 for concluding that both are the Eudoxids of one species. In the basoventral 

 concavity they agree so well with the bract figured by Huxley, that I have no 

 doubt that they are specifically identical with it. And although it is not alto- 

 gether certain that the bract in question belonged to ,4. haeckeli, there is every 

 reason to suppose that such was the case. There is thus a strong probability 

 that the Eudoxids Amphiroa angulata Huxley, and A. dispar Bedot, are 

 the free cormidia of Abyla haeckeli; but to determine conclusively whether this 

 view is correct will require an examination of specimens of that species with 

 stem and appendages intact. 



So far, A. haeckeli is known only from the Malaysian region and from the 



