470 MK. H. T. BEOWNE ON [Mar. 17, 



The stomach is on a very short peduncle, and has six short pro- 

 longations or lobes from which the radial canals start. The mouth 

 is variable in shape, being either round or with four to six lips. 

 Six radial canals run from the lobes of the stomach direct to the 

 ring-canal without giving off any branches. Six tentacles, equal in 

 size, on the margin of the umbrella, one opposite the termination 

 of each radial canal. The basal bulb of each tentacle is large and 

 conspicuous, containing dark brown or blackish pigments. Midway 

 between every two tentacles a small cluster of nematocysts is situ- 

 ated on the ex-umbrella just above the margin. 



This stage corresponds to the description given by Hincks of the 

 medusa of Lar sabellarum. 



Second Stage. Twelve uniform tentacles. — The commencement of 

 the second stage is indicated by the growth of six small bulbs on 

 the margin of the umbrella, midway between the primary tentacles. 

 From each of these bulbs a tentacle grows until it resembles in size 

 the tentacles belonging to the first stage. A bulb on its first ap- 

 pearance is of a yellowish-brown colour, but when fully grown it 

 becomes dark brown or black. As soon as a bulb makes its appear- 

 ance on the margin of the umbrella, a branch is given ofi from the 

 radial canal and joins the ring-canal opposite the bulb. 



The branch is always given ofi from the same side of each 

 radial canal, and leaves the canal about the middle of its course on 

 the side of the umbrella. The six lobes of the stomach have now 

 become more conspicuous and extend over the upper part of the 

 sub-umbrella. It is on the sides of these lobes that the repro- 

 ductive cells develop. The clusters of nematocysts belonging to 

 the first stage still remain, and twelve new clusters appear close to 

 the margin, one midway between every two tentacles. Medusso 

 belonging to the second stage are about 2 mm. in diameter. 



Third Stage. Eighteen uniform, tentacles. (Plate XVI. fig. 4). — 

 This stage commences with the growth of another set of six bulbs, 

 which develop tentacles in the same manner as in the previous 

 stage. 



The new bulbs are not on the same side of the main radial canals 

 as those belonging to the second stage, but on the opposite side. A 

 new branch leaves each radial canal nearly opposite the junction of 

 the first branch and runs down to the bulb on the ring-canal. In 

 this stage each radial canal has two brancli canals, one on each side 

 of it, the whole forming a kind of thi'ee-pronged fork, with a ten- 

 tacle at the end of each canal. At this stage the reproductive cells 

 are clearly visible, and are situated along the six lobes of the stomach 

 and arch over the top of the sub-umbrella, forming a star-like pat- 

 tern of a yellowish-brown colour, hence Forbes's specific name of 

 the medusa. 



The clusters of nematocysts belonging to the first stage, and 

 probably some belonging to the second stage, have now disappeared, 

 and a now cluster is developed midway between every pair of ten- 

 tacles. The clusters of nematocysts form an excellent mark for 



