MEDUS.E. I. 



(the cross-arms) are seen, from the stomachal cavity, as deep, narrow grooves (Plate V, fig. 4). 

 From the distal ends of these four grooves issue the four radial canals which, from these points, run 

 upwards along the ])eduncle (Plate V, fig. 5). The openings of the radial canals may be complete! v 

 closed by contraction of the borders of the grooves, thus the lumen of the canals being separated from 

 the cavity of the stomach; in the stomach figured in Plate V, fig. 4, the openings on the left side 

 have been closed in that manner. 



The basal jiart of each radial canal is a little widened and has a number of fine, transverse folds. 



The mouth-opening is wide and is provided with four large, pointed lip.s, complexlv folded and 

 with a crenulated margin (Plate V, fig. 5). 



There are four straight radial canals and a very narrow circular ves.sel. The mode of attach- 

 ment of the radial canals to the subumbrella (and the stomachal peduncle) is remarkable (see Plate \'. 

 fig. 10). The usual median streak of high entodermal cells is very narrow, but the uppermost parts of 

 the lateral entodermal layer of the canal on both sides are attached to the subumbrella, the ectoderm 

 and the mesosarc leaving the subumbrella at some distance from the median streak; thus the line of 

 attachment has secondarily become rather broad. 



The gonads are developed upon both sides of the radial canals from the attachnieul to the 

 subumbrella, leaving a narrow median line free on the ventral edge. Though the line of attachment 

 to the subumbrella is straight, the lateral walls of the canals are, in the parts carrying the gonads, 

 \ery much folded in a fairly regular, wavy manner. The gonads e.xtend partly over the subumbrella 

 from the base of the peduncle towards the bell-margin, reaching nearly to the circular vessel, partl\- 

 downwards along the peduncle, ceasing at a distance of some few millimeters above the stomacli. The 

 gonads attain their highest development and are most highly folded upon the subumbrella, gradnallv 

 tapering during their course downwards upon the peduncle. Sections laid through different parts of 

 the gonads of one and the same specimen show, however, that the sexual i)roducts are in the same 

 state of maturit\- in ever>- part. In the higliK- folded parts the ventral median line, free of gonads, is 

 sometimes fairh' broad, sometimes ver\' narrow, shaped like a dee]) furrow, and is, in such cases, hardly 

 visible, except in sections. 



The usual number of tentacles is 16. When fully expanded, the length of the tentacles is about 

 3 times the diameter of the bell. The tentacular bulbs (Plate V, figs. 6, 7, 8) are oblong, pear-shaped, 

 gradnallv passing into the thread-like part of the tentacles. The ectoderm of the bulb is .somewhat 

 thickened, equally developed all round the bulb (Plate \', fig. 8). Proximally the abaxial side of the 

 bulb is sharply set off from the exumbrella. There is a well-developed, hollow, entodermal basal .spur 

 projecting into the gelatinous substance of the exumbrella, curving outwards and upwards, its abaxial 

 .side resting close to the exumbrellular epithelium, which is slightly thickened in this part (Plate \', 

 fig. 8). Above each of the tentacles there is a slight, rounded prominence of the exumbrella (Plate A', 

 fig.s. 6 and 7); this mav be due to contraction owing to the preservation. The points of insertion of 

 the tentacles are usualh not quite equidistant. 



Between the tentacles there is a large nimiber of marginal warts (see Plate V, fig. 6). The ba.se 

 of the warts is rectangular, the warts being placed closeh' together. In some cases the\- are separated 

 from each other by a sharp furrow, but sometimes they pass gradnalh- into one another; it is difficult, 



