bo E. PERCIVAL 



pit on one non-terminal ephyra but shows nothing further. 

 Heric concludes that they are new structures. 



In the same way there is little information on the regenera- 

 tion of the oral disc of the polyp which remains after strobihza- 

 tion. Heric indicates that the development of the proboscis 

 is similar to that of the manubrium of the ephyra, but says that 

 the four strands connecting the polyp with the ephyra above 

 pass directly to the wall of the enteron after having become 

 dissociated from the proboscis. According to this the polyp 

 would have no septal ostia, and the oral end of the longitudinal 

 muscle would be absent for a time. Whether this is so or not 

 in Chrysaora I cannot say, but, as shown below, it is not the 

 case in Aurelia. He goes on to say : ' How the oral disc (of the 

 polyp) is connected with the septa can be answered just as 

 little as the question whether the septal muscle, in its course, 

 is transformed by the remainder of the polyp to be replaced 

 by a new muscle originating from the oral disc, or whether 

 it is preserved and enters (secondarily) into connexion with the 

 oral disc '. 



A complete ephyra becomes free by the gradual extension of 

 the connecting strands and by their final rupture. Prior to 

 this event the exumbral opening has closed. Heric believes 

 that this closure takes place simultaneoush' with the breaking 

 of the strands. He did not find any trace of longitudinal muscle 

 in an ephyra immediately after detachment. 



2. New Investigation. 



The material used in this work was obtained from the Dove 

 Marine Laboratory, Cullercoats, Northumberland, and was 

 killed and fixed in saturated aqueous corrosive sublimate 

 solution with 2 per cent, glacial acetic acid. Delafield's haema- 

 toxylin, and iron haematoxylin and eosin were used to stain 

 the serial sections. Delafield's haematoxylin is very useful 

 for general observations, but the latter stains were better for 

 determining the limits of ectoderm and endoderm, especially 

 in the early stages of the manubrium. 



it should be understood that my description of the forma- 



