OF THE HYDKOMEDUS.E. 371 



In many respects MefcschnikofF's observations upon the structure of the egg-embryo 

 are in conflict with Uljanin's account; but as it is impossible to reconcile the statements 

 of tha latter writer with oar general knowledge of the subjeot, I think we may safely 

 conclude that MetschnikoflPs account is the more trustworthy. 



Both authors agree that tlio egg-embryo of the species which occurs in the stomach 

 of Carmarina is dein-adjd and has no umbrella, while Metschnikoff shows that the 

 proboscis also is absent. 



The next paper in historical order is a short one which Fewkes published in 1881 

 (19). lie gives a brief account, with one figure, of Cunina larvae which he found at 

 Villafranca, attached to the gastrostyle of Carmarina, and he verifies Uljanin's state- 

 ment that the larvae are sometimes found on other parts of the medusa. He has ob- 

 served them on the umbrella. 



The youngest larva which he found was attached to the tip of the gastrostyle. It was 

 solitary and he regards it as an egg-embryo destined to develop a stolon and to give 

 rise to medusa-buds. He states tbat it was furnished with a long proboscis and a di- 

 minutive bell, and was almost identical with the youngest larva figured by McCrady, 

 which, however, has a short prob >seis and no bell, and it is impossible to reconcile 

 his account with the observations l>y Uljanin and Metschnikoff, which show that the 

 nurse is, in the species which they found in Carmarina, greatly degraded and has nei- 

 ther proboscis nor umbrella. His description is inaccurate, or else his species is a new 

 one; and if the latter is the case it is to be hoped that his drawings and a more minute 

 description will soon be published. 



Fewkes attempts to show that there is a morphological similarity between a Siphono- 

 phore and the clusters of Cunina buds which are found in Carmarina. In support of 

 this view he states that "these clusters or colonies of young Cuniuae, as is well known, 

 ultimately dissolve their connection with the stolon and swim away as free medusa'.' 1 If 

 he means by this sentence that the clusters or colonies swim away, the phenomenon is 

 neither " well known" nor supported by a single published observation. If he means 

 simply that each msdusa-bud is detached from the stolon and becomes a free medusa, 

 there is little resemblance to a Siphonophore; nor does our knowledge of the subject 

 furnish any basis for his statement, p. 305, that the stolon which carries the buds is a 

 modified proboscis. 



He says " Cunina has become degenerated by its parasitism or commensalism so that 

 the proboscis with young budding from it alone remains. Its bell has gone, the mouth 

 opening is no longer functional, and the proboscis, which has elongated into a stolon 

 attached to the body of a host, is closely crowded with the young;'' but Metschni- 

 koifs account of this particular form, shows that here, as in all other Cuninas which 

 have been studied, the stolon arises from the aboral surface and has nothing to do 

 with the proboscis. 



This paper completes the long list of observations upon this interesting subject, 

 and it may now be well to summarize the history of research regarding the parasi- 

 tism of Cunina. 



1. In JEgineta and .iEginopsis the egg gives rise I" the ciliated planula, which ac- 

 quires a mouth, a short proboscis and tentacles, and thus becomes a free hydra or 

 actinula, which is directly metamorphosed into a medusa. One egg gives rise to a 



