36 Bulletin, Vanderbilt Marine Museum, Vol. IV 



Color: Transparent, colorless, with a touch of yellow due to oil 

 in the oleocyst. 



Life history : Imperfectly known. 



Technical description: Consult Huxley, T. H., (1859), and Bige- 

 low, H.B. (1911). 



References : Aglaismoides eschscholtzii Huxley, T. H., The Oceanic 

 Hydrozoa, p. 60, pi. 4, fig. 2, 1859, London. 



Abylopsis eschscholtzii Bigelow, H. B., Mem. Mus. Comp. Zool., vol. 

 38, p. 226, pi. 14, figs. 1-5, pi. 15, fig. 1, 1911. 



Abylopsis tetragona (Otto). 



Type: Otto's type came from the Mediterranean and is deposited 

 in the Museum at Breslau. 



Distribution : "Widely distributed in the Mediterranean, the tropi- 

 cal Atlantic, the West Indian region, the eastern and western tropical 

 Pacific, the Malaysian region and the Indian Ocean. Bathypelagic. 



Material examined : The Eudoxid stage of this species was taken 

 in very good condition in the dredge down 400 fms., bottom depth 

 500 fms., off St. Raphael, bearing S. S. E., distance 9 miles S. of 

 France, Mediterranean Sea, March 23, 1927, by the "Ara." 



Technical description : There are several excellent well illustrated 

 descriptions of this species. It is more similar to A. eschscholtzii than 

 any other members of the genus, but is readily distinguished there- 

 from by its very large size, its relatively much longer nectophore 

 which is between four and five times as long as the anterior necto- 

 phore. The asymmetry of the nectophore in tetragona is very marked. 

 The hydroecium is likewise diagnostic, the right wing being only 

 slightly serrate on its transverse basal margin; the left wing being 

 toothed throughout its length. The canals of the nectosarc are pecu- 

 liarly arranged in tetragona, while in eschscholtzii they have the usual 

 radial distribution. 



The free Eudoxid stage of this species has likewise been well 

 described. The outstanding diagnostic feature of this stage is that its 

 dorsal facet is subrectangular in tetragona, but is regularly pentag- 

 onal in eschscholtzii; the ventral facet is straight in tetragona, deeply 

 convex in eschscholtzii; the basolateral facets also differ in their 

 proportions. 



References : Pyramis tetragona Otto, p. 306, taf . 42, figs. 2a-2c, 1883. 

 Abylopsis tetragona H. B. Bigelow, Mem. Mus. Comp. Zool., vol. 38, 

 p. 224, pi. 14, figs. 6, 7, pi. 15, fig. 2, 1909-1911. 



