86 • THE OCEANIC HYDROZOA. 



Fam. ATHORYBIAD.E. 



Genus ATHORYBIA [Eschscholz). 



The hydrosoma, which is not distinctly separated into pneumatophore and ccenosarc, is 

 spheroidal, the pneumatocyst nearly filling its cavity. There are no nectocalyces. The 

 hydrophyllia are arranged around the ccenosarc, on the proximal side of the other appendages. 



Athorybia rosacea (?). PI. IX. 



Athorybia rosacea, Eschscholz. 1839. 

 — — Kolliker. 1853. 



That portion of the hydrosoma which represents the pneumatophore is spheroidal, but 

 somewhat pointed above, and has its apex surrounded by a series of radiating dark-brown 

 striae, each made up of dots. Its general colour is pink. The polypites have a lightish-red 

 hue, shading off into pink at their apices. The tentacles are yellowish or colourless, with 

 dark-brown sacculi. 



The hydrophyllia are lanceolate, tolerably straight in their upper halves, but greatly 

 incurved below. The upper and' outer surface of each is convex, the lower and inner concave. 

 Six longitudinal rows of small thread-cells mark the outer surface. The basal or upper portion 

 of the hydrophyllium is broad, and presents, on each side, a notch or shoulder, where it joins 

 with the narrower neck, by which it is connected with the broad lanceolate blade. These 

 shoulders overlap, or are overlapped by, those of neighbouring hydrophyllia. The axis of 

 each hydrophyllium is traversed by a narrow, tubular, csecal phyllocyst, M'hich runs nearer the 

 inferior surface, and is wider and ciliated internally in the younger organs. The larger and 

 more conspicuous hydrophyllia are an-anged in a circle around the globular hydrosoma above 

 its equator, but a few smaller ones are to be observed among the appendages of the under 

 surface. These were polypites, tentacles, and reproduptive organs. 



Of the polypites, the distal ones,' or those attached more towards the centre of the under 

 surface, especially one or two, were the larger and more active. Their inner wall was provided 

 with villi for about its basal two thirds ; some of these villi were short and thick, others thinner 

 and elongated. The latter were often jagged or produced into small points at their 

 extremity. The villi contained large clear spaces (vacuolse) in their interior. 

 Young undeveloped polypites were scattered among the perfect forms. 

 The tentacles sometimes appeared to come off from the wall of the ccenosarc itself, 



' The upper and outer series were so similar to the others that they are not specially distinguished 

 in my notes, so that I cannot say whether they have the structure described by Kolliker in the " Fiihler," 

 or bvdrocysts of his Athorybia, or not. 



