1896.] BBlTIsa HtDEOlDS A»D ItBDtTS^. 465 



elongate and are soon seen t.o be dilated into bulb-like expansions at 

 their extremities. The bulbs increase in size and come in contact 

 by their sides ; while one of them, enlarging much more rapidly 

 than the other three, gives a marked preponderance to its side 

 of the bud and makes the distal end of the bud appear obliquely 

 truncated. It then begins to extend itself beyond this distal end 

 into a thick hollow tentacle." 



Allman also obtained free-swimming medusae from his hydroids, 

 which he has described and figured in his monograph. These are 

 similar to the figures given by Hodge, and have a margin at right 

 angles to the longitudinal axis of the umbrella. 



Erom the description given by Allman of the development of the 

 medusa, it appears that the rapid growth of the large tentacle-bulb 

 extends the length of the umbrella more on that side than on the 

 other, and in this way the margin becomes oblique, as one side of 

 the umbrella is longer than the other. It is clear from the de- 

 scriptions given by Hodge and Allman, that the obliqueness must 

 disappear before the medusa is liberated, as they figure the free- 

 swimming form with tho margin in the normal position. I think 

 that these observations on tho obli(iuenes3 of the margin of the 

 umbrella strengthen the view that the British and Norwegian 

 specimens belong to the same species, and I have again united 

 them under the old name of Corymorplia nutans. 



Forbes has given only two species in his medusoi'd genus Steen- 

 strupia, namely S. rubra and S. Jlaveola. I agree with Haeckel 

 in considering that these are not distinct species. The character- 

 istic features of these medusoe are similar to those of the medussB of 

 Corymorplia nutans. The figures given by Forbes of Stcemirupia 

 show the characteristic points of the species, but they are not 

 good figures of a healthy specimen of the medusa of Corymorplia. 



Hodge recognized the similarity between Steenstrupia and the 

 medusa of Corymorplia, but was led by Forbes's figures to consider 

 the latter as another species. 



Allman states the medusa of Corymorplia " belongs to a form to 

 which Forbes has given the generic name of Steeiistrupia." Sars 

 (1877) writes, " It is even not improbable that when disconnected 

 from the parent animal, they (the medusae) may develop themselves 

 into the species described by Forbes under the name of Steenstrupia 

 rubra." 



During my visit to Valencia Island in 1895, I found medusae 

 corresponding to the descriptions and figures given by Hodge and 

 Allman of the medusa of Corymorplia nutans (PI. XVI. fig. 1). They 

 were often exceedingly abundant during April and May, and some 

 occasions many hundreds could have been quickly collected. One 

 day I thought that a lovely Siphonophore had entered the net, but 

 closer examination showed some dozens of these medusae, caught 

 by the tentacle, on a piece of cotton about an inch and a half long. 



The umbrella is bell-shaped, nearly twice as long as wide ; the 

 aboral end of the umbrella is extended into a spine-like process, 

 which is always present, and is a characteristic feature of the 



Peoo. Zool, Soo.— 1896, No, XXX. 30 



