BY R. VON LENDENFELD, PH.D. 433 



from a sheltered harbour, to a great distance, but that a boundary 

 is set to any such spreading, if a harbour suitable for a breeding 

 place is too far away. 



Although the Rhizostorna? of the Northern Hemisphere are so 

 much better known than those of the southern, the number of the 

 species known here is far greater than there. We may, therefore, 

 be allowed to maintain that the Rhizostoma3 are incomparably 

 more numerous in the Southern than in the Northern Hemi- 

 sphere ; which is doubtless in connexion with the greater expanse 

 of water south of the Equator. 



In comparing the whole of the Scyphomedusae, we have to meet 

 the difficulty, that in proportion but very few of the smaller and 

 more delicate forms occurring in the Southern Hemisphere are 

 known. Of the 210 Scyphomedusae with which we are acquainted, 

 104 have been found in the Southern Hemisphere. 



From the reasons inferred to above the comparison of the 

 Rhizostornge alone gives a more exact idea of the distribution than 

 the comparison of all the Scyphomedusae would afford. 



