MEDUSAE. 135 



Family: MAKGELIIDjE, Haecket,, 1877. 



Cytaeis, Eschscholtz, 1829. 



Margeliida? with four single perradial marginal tentacles, and with unbranched oral 

 tentacles. 



Cytaeis herdniani, n. sp. Plate I., fig. 1 ; Plate IV., fig. 12. 



Description. Umbrella somewhat bell-shaped, about as high as broad, with fairly 

 thick walls. Velum narrow. Stomach large, about as long as wide, situated on a 

 short peduncle, and extending a little over half-way down the cavity of the 

 umbrella. Mouth circular (expanded) with about 50 to 60 oral tentacles, which are 

 unbranched and evenly distributed. Four broad radial canals. Gonads forming 

 four large perradial swellings, and extending the whole length of the stomach. Four 

 thick tentacles, perradial, with very large basal bulbs, which are somewhat triangular 

 in shape. 



Size : Umbrella about 3i millims. in width and height. 



Locality : One specimen from Chilaw Paar on March 20, and one from Cheval 

 Paar on November 1 1 . 



Notes. Of these two specimens, one is an adult and the other is an intermediate 

 stage. The stomach is cross-shaped in transverse section, and the gonads occupy the 

 sides of the cross. The oral tentacles have a small round terminal cluster of 

 nematocysts. The four marginal tentacles are thick and have a dark central band 

 of pigment (perhaps a brilliant colour in the sea). A transverse section (fig. 12) 

 shows that the pigment granules are confined to the endoderm cells, which form a 

 solid central band of cells along the tentacle. The pigment granules form a dense 

 layer round the periphery of the endoderm, and are also scattered along the walls of 

 the cells. There is a fairly thick layer of mesoglcea and an extra thick ectoderm 

 which contains an enormous number of nematocysts, closely packed together. The 

 basal bulbs are very large and extend some way up the umbrella. There is a layer 

 of dark pigment along the inner side of the bulb, and a thick whitish mass of cells 

 on the outer side. Sections were not cut of the basal bulb, but the dark pigment 

 granules would probably denote the endoderm and the external whitish cells the 

 ectoderm. The specimen at the intermediate stage in development is about 2 millims. 

 in width and height. It has four marginal tentacles, fewer oral tentacles, and smaller 

 gonads than the adults. 



This species is nearly related t<> Gytoeis nigritina and Cytteis macrogaster of 

 Hakckel. It differs from them in having many more oral tentacles, in the shape 

 of the basal bulbs, and in the structure of the tentacles. 



Family: WILLIIILE, Forbes, 184-8. 

 Proboscidactyla, Brandt, 1835, ex Browne, 1904. 

 Williidse with four radial canals leaving the stomach. 



