M KIM'S. K. 



31 



reflected, black iii transmitted light. I noticed that a few of the cordyli of 

 Ptychogena antarctica were chalk-white, and this conspicuous whiteness was also 

 present in patches on the surface of some of the gonads. I am unable to explain the 

 cause of the whiteness, but it is evidently due to minute particles, which are perhaps 

 products of the decomposition of the endoderm. The white cordyli mounted in 

 balsam show no cellular structure, but seem to be simply masses of granules. 



The two intermediate stages in the 'Southern Cross' collection taken on 19th 

 May, 1899, are in a bad condition. Their connection with the large specimen, 

 mentioned above, was traced by the shape of the basal bulbs of the tentacles and by 

 the presence of the long club-shaped cordyli. The umbrella has the appearance of 

 being hemispherical in shape, and measures about 25 mm. in width. The margin 

 of the umbrella is crowded with tentacles, the.number of which is estimated at about 

 one hundred. Long cordyli were found between some of the tentacles, but not 

 between every two tentacles. Their scarceness is no doubt due to the condition of the 

 specimens. The better of the two specimens shows the gonads with the characteristic 

 folds and a stomach. Unfortunately the stomach and gonads are compressed into a 

 flat mass and matted together. Dissection could only be incompletely carried out 

 owing to the rotten condition of the tissues. There is every appearance of a large 

 central stomach, which hangs down in the umbrellar cavity, and a large mouth 

 with a folded margin. The gonads extend along the radial canals from the base of 

 the stomach nearly to the circular canal. The radial canals can be traced up to 

 the centre of the umbrella, where they meet, and probably the stomach hangs down 

 from them. 



Mr. Borchgrevink may have alluded to this species in his book " First on the 

 Antarctic Continent," p. 125 : " 10th May, 1899. In the forenoon I had discovered 

 a small white clear jellyfish with a distinct blue cross in it." The gonads of 

 the two intermediate stages showed a deep bluish-black colour when, some years 

 ago, I first examined them ; but now the colour has changed to a dark brown 

 (in alcohol). 



The single specimen in the ' Discovery ' collection is in a fairly good state of 

 preservation, but is mutilated and out of* shape. It was useful for the description 

 of the gonads, which arc fairly perfect in this specimen and contain large ripe ova. 

 The umbrella is rather thin, and is about 35 mm. in diameter. 



Pti/clm/n'iia antarctica is distinguished from Ptychogena lactca by the absence of the 

 conspicuous diverticula on the radial canajs, and by the colour of the tentacles, which 

 are red. 



Mr. Bigelow (1909) described a new species P. erythrogonon, from the eastern 

 tropical Pacific (between Galapagos Islands and Callao). It has well-marked specific 

 characters, possessing a very thick globular umbrella and about 80 tentacles. Its 

 coloration is a very brilliant brick-red. 



