188 Prof. Carl Glaus on the 



with the Medusa-theory, as a new theory reconciling the 

 two. 



Under .these circumstances I may venture to reproduce 

 some passages which are decisive upon the present question, 

 especially as the statements made in both memoirs seem to 

 be but little known generally. 



In the above-cited chapter of ray memoir on Halisfemma 

 the arguments which are in opposition to the Medusa-theory 

 of Huxley and Metschnikoff are first of all discussed. Then 

 it is said (p. 48) : — " But the very tendency to the re])etition 

 of similar organs which Metschnikoff is obliged to ascribe to 

 the Siphonophoran organism carries him from his different 

 starting-point (Medusa) back again to the theory of poly- 

 morphism, which he thinks he has confuted so very decidedly. 

 For in reality if a second bract or a new nectocalyx, a second 

 or third polyp or feeler be added, the stem of the primary 

 stomach or Medusan stomachal peduncle becomes, I readily 

 admit, like a Sarsia prolifera, a kind of proliferating stem 

 with many hundreds of appendages. But by this, at the 

 same time, the conception of the Siphonophore as a multi- 

 2^Ucity of repetitive Medusan parts, purposely reduced Me- 

 dusoi ivith special functions, is manifested, and the theory of 

 polymorphism and of the division of labour is perfectly con- 

 firmed, for if the buds on the stomachal peduncle of Sarsia 

 here brought into comparison shape themselves into new 

 Medusaj, and therefore are morphologically the foundations 

 of new individuals, the same applies to the sprouting Siphono- 

 phoran appendages, whether these, as genital nectocalyces, 

 assume the perfect Medusan form, or as feelers and polype 

 (gastric sac), relatively as nectocalyx and bract, merely 

 reproduce parts of Medusae, i. e. reduced Medusai, and conse- 

 quently are only able to perform parts of the functional 

 work. 



" The difference of Leuckart's interpretation of the Siphono- 

 phoran body as a polymorphic free-swimming Hydroid-stock 

 therejore fundamentally relates only to the startiny-fbrm, which 

 Leuckart, in accordance with the then existing state of the 

 theory of development, thought was to be recognized in the 

 larva which, as an isolated gastric sac, founded the colony, 

 whilst, according to the more recent views of developmental 

 history, it appears to be represented by the parts of a 

 Medusa. 



" But if, as the results of later investigations will perhaps 

 furnish decisive data to show, the morphologically higher 

 Hydroid-form, the Medusa, be really the starting-point in the 

 production of the Siphonophore, the polymorphism of our 



