NOTE ON THE DEVELOPMENT OF THE VERSURID^E. 



Plate V. 

 By E. Vox Lendenfeld, Ph.D. 



Although the early stages of development, the Gastrula and 

 Scyphistoma of some of those Phizostomse which possess a single 

 Sub-genital space, the Monodenmia of Haeckel, are known 

 of one or two species ; the later stages, the Ephyra and the 

 Metamorphosis of these Medusas is unknown. Only Haeckel 

 observed young stages of a Medusa belonging to the Crambessidae, 

 but these also had attained a size of from 30 to 40 mm., and 

 appeared similar to the adult animal. (1.) 



I have had the luck to capture some very young stages of the 

 Phyllorhiza punctata, a new species described in another paper (2), 

 which is very abundant in Port Jackson. The smallest of these 

 measured 15 mm. across the disk, and I obtained an unlimited 

 number of specimens from this size upward to the adult animal, 

 which measures half a meter across the Umbrella. In colour and 

 shape these small larvse are similar to the adult animals. 



Claus (1) has described the development of the Mouth-arms in 

 Rhizostoma Cuvieri (Pilema pulmo. Haeckel), which belongs to 

 the Family Torenmidse. In our species the Mouth-arms follow in 

 their development a similar course as that described by Claus. 



The Sub-genital space appears to be formed in the way that 

 Haeckel supposes, but I am as yet not quite sure on this point. 



(1.) Since this paper was read I received " Untersuchungen tiber die 

 Organisation und Entwiclcelung der Medusen." By G. Claus, in which 

 paper the Metamorphosis of Catylorhiza tuberculata is described (page 

 43, f. f.) The characteristic peculiarity in the Metamorphosis of Phyllorhiza 

 punctata — the decrease of the number of marginal bodies does not occur in 

 Cotylorhiza. The cause of the brown colour in the latter is ascribed by 

 Claus to Zooxanthellae in a similar manner as by myself in Phyllorhiza. 



(2.) Proc. Lin. Soc. N.S.W., Vol., IX., p. 296. 



