ANTHOZOA HYDROIDA. 



19 



Fig. 3. 



stay not to inquire how this fact quadrates with the " law of 

 development" which has of late heen advocated with more 

 speciousness than knowledge ; but we must needs breathe a 

 little, while we contemplate this diversion in the plan of crea- 

 tion, — this retrograde step in life, — not unexampled in others 

 of these lower organisms. The young is a nomade creature 

 free to go whither it will, and hence its higher organization — 

 senses to guide, and muscles to move the body to and fro. So 

 alike indeed are they both in form and manners to the Medu- 

 sae, that they have been described as members of the latter 

 class by experienced naturalists ; and it is not until they have 

 put away the vagrancy and liveliness of youth, that they 

 become staid and fall down into an inferior order. Even in 

 their Medusa stage these embryos often contain ovules whence 

 other young are to proceed. 



But the Tubularinse are also propagated by ovules, which 

 undergo in their development no change that amounts to a 

 metamorphosis. These originate in the same ovisacs as the 

 others, and commence their growth in the same manner ; but 

 at an early stage they become separate fi-om the pulp whence 

 they have proceeded, and the process of organization goes on 

 in isolated germs, as in higher animals. The development 

 here is gradual and regular. At the time of its extrusion 



from the ovisac, this ovule has attained to somewhat the 



c2 



