MEDUSAE. 139 



tentacles are attached to a slight thickening of the umbrella and curl over the margin. 

 The nematocysts along the tentacle are arranged in transverse bands which do not 

 quite meet on the inner side of the tentacle, so that a shallow groove is formed along 

 the inner side, running the whole length of the tentacle. The marginal bulbs have 

 a patch of blackish pigment at their apex. 



This species comes nearest to Euthna mira and Eutima insignis, but is distinguished 

 from them by the shape of the basal bulbs. 



Octorchis, Haeckel, 1864. 

 Octorchis orientalis, n. sp. Plate III., fig. 4. 



Description. -Umbrella probably hemispherical, a little broader than high, and 

 moderately thick. Peduncle of the stomach long, quadrangular in transverse 

 section, and with a broad roundish base. The length of the peduncle is about twice 

 the diameter of the umbrella. Stomach small, about as long as broad. Mouth with 

 four short lips and a deeply folded margin. Gonads upon the peduncle of the 

 stomach and also upon the sub-umbrella. The gonads occupy the greater length of 

 the peduncle, extending along the radial canals, beginning a little way below the 

 base of the peduncle and terminating close to the stomach. The gonads upon the 

 sub-umbrella usually occupy the central third of the radial canals, or the outer half, 

 but do not reach to the margin of the umbrella. Four long perradial tentacles, with 

 long tapering cylindrical basal bulbs. About 18 to 20 marginal bulbs in each 

 quadrant of the umbrella, each one with a lateral cirrus. Eight marginal sensory- 

 vesicles. 



Size : Umbrella about 5 milium to 6 millims. in diameter. 



Locality : Galle Bay, one specimen on June 5, seven on June 12, and two on 

 August 21. 



Notes. None of the specimens are in good condition, the umbrella being so 

 flattened out and crumpled that it is not possible to draw a figure of it. Some of 

 the largest specimens have the gonads upon the peduncle in a series of folds (fig. 4), 

 but it is possible that the folding may be due to the contraction of the peduncle. 

 The gonads upon the peduncle are much larger and longer than those ujdoii the 

 sub-umbrella, the latter forming merely a thin narrow band along the radial canals. 

 The marginal bulbs are very small and inconspicuous. The cirri are very slender and 

 have a small terminal cluster of nematocysts. The sense-organs are situated near 

 the tentacles. They are very small and globular in shape, their otoliths not visible. 



Notes on Intermediate Stages. 



(a.) Umbrella about 2 millims. in diameter. Peduncle about 5 millims. in length, 

 with gonads just appearing upon it. Four tentacles. Cirri present. About 9 

 marginal bulbs in each quadrant. Eight sense-organs. 



T 2 



