ON A SPECIES OF SIPHONOPHOEE OBSEEVED AT PLYMOUTH. 215 



The form I have described was also noticed at Plymouth by 

 Mr. G. C. Bourne, who states in his report of his cruise in H.M.S. 

 '' Research," this Journal, vol. i. No. 3, that he also obtained it oif the 

 south-west coast of Ireland, and that it seems to be the Muggisea 

 Kochii of Chun and Haeckel. I have indicated above the points by 

 which it is definitely distinguished from Mtiggiasa Kochii. 



In the paper already cited, Chun gives a detailed account of the 

 interesting and complicated changes which he discovered to take 

 place in the life-history of Muggisea Kochii. The egg first develops 

 into a stage resembling Monophyes, in which the nectocalyx is smooth 

 and without ridges. The characteristic pyramidal nectocalyx then 

 develops and separates, carrying the siphosome with it. The cormidia 

 or eudoxomes, when fully developed on the tubular stem or siphosome, 

 become free, and continue to live as independent organisms or 

 colonies, which were originally described under the name Eudoxia 

 Eschscholtzii. The Eudoxia bears a genital calyx resembling a 

 nectocalyx in shape, and this produces ova or spermatozoa. Each 

 Eudoxia is unisexual, but produces several genital calyces in succes- 

 sion, all of the same sex. From the egg of the Eudoxia develops 

 the Monophyes-like larva and the series of stages recommences. 

 Probably the Muggisea atlantica has a similar life-history, but I was 

 unable to make a more complete study of it, partly because I had 

 other work to attend to, partly because I could only obtain pelagic 

 matei'ial when the total results of the day's collecting were brought 

 in somewhat late in the afternoon. The specimens as brought to me 

 were always in the condition shown in my figures, only a short 

 basal portion of the siphosome remaining attached to the nectocalyx. 

 Detached eudoxomes were present in the bottles, but in a somewhat 

 damaged condition. 



