40 THE OCEANIC HYDROZOA. 



Genus ABYLA {Quoi/ and Gaimard). 



The proximal nectocalyx differs widely from the distal one in form and size, the latter 

 having an elongated, more or less mitrate shape, while the former presents many straight- 

 sided, plane, tetragonal, pentagonal, or hexagonal facets. 



The proximal nectocalyx is shorter than the distal. The hydrophyllia are thick 

 and facetted, or produced into points on their outer surface, and their edges do not overlap 

 spathe-wise. 



Abyla pentagona. pi. II, fig. 2. 



Pyramis tetragonu (?) Otto, 1823. 



Caipe pentaffona, Quoy and Gaimard, 1827. 



Abyla pentagona, Eschscholz, 1829. 



— — Delle Chiaje. 

 _ _ Kolliker, 1853. 



— — Leuckart, 1853. 



— trigona, Vogt, 1854. 

 Aglaisma Baeri, Eschscholz, 1825. 



_ _ Busch,1851. 



— pentagonum (?), Leuckart, 1853. 

 Eudoxia cuboides, idem, 1853. 

 Aglaismoides {?), Huxley {infra). 



The proximal nectocalyx has not more than one third the length of the distal. 

 If it be placed with the axis of its nectosac vertical and its hydroecium backwards, 

 it will be found to be four-sided and to have two parallel, flat, pentagonal faces, one of which 

 is anterior and the other posterior. Each pentagon has one of its angles superior, and 

 one side consequently inferior. The lateral faces are divided into two portions, one supero- 

 lateral, four-sided, looks upwards and outwards, and meets its fellow of the opposite side 

 in a ridge which joins the superior angles of the anterior and posterior faces. The other, 

 infero-lateral, also four-sided, looks downwards and outwards, and is produced posteriorly 

 and inferiorly into the lateral wall of the hydroecium, as the posterior face is produced into its 

 posterior wall. Anteriorly, the lateral plates are united by an undivided, anterior septum, 

 which, like the posterior, has its lower edge deeply emarginated and serrated. 



The nectosac opens upon the truncated anterior moiety of the inferior face of the organ. 

 It is subcylindrical, and ends above before reaching the superior edge of the nectocalyx. The 



