APPENDIX. if, 



" Bringing, now, the Evolution hypothesis to bear upon the question, 

 it would follow that the Graptolite may be viewed as an ancestral form 

 of the Sertularian hydroids, a form having the most intimate relations 

 with the Rhizopoda ; that hydranths and hydrothecae became developed 

 in its descendants, and that the Rhizopodal Graptolite became thus 

 converted in the lapse of ages into the Hydroidal Sertularian. 



" This hypothesis would be strengthened if we found it agreeing with 

 the phenomena of individual development. Now, such Pluraularidse as 

 have been followed in their development from the egg to the adult 

 state do actually present well-developed nematophores before they 

 show a trace of hydrothecte, thus passing in the course of their embryo- 

 logical development through the condition of a Graptolite, and recapi- 

 tulating, within a few days, stages which it took incalculable ages to 

 bring about in the palseontological development of the tribe." 



EVOLUTION BY DEGRADATION. 



It is hardly surprising that the theory of Evolution by Regression, 

 advocated by Dr. Dohrn, of Naples, and in this country by Professor 

 Ray Laukester, should have met with some opposition, so greatly does 

 it multiply the difficulties of ascertaining the true phylogenetic affinities 

 between living things. Supposed links in the ascending series have 

 now to be tested from above as well as from below ; and notwithstand- 

 ing the great prominence given in recent systems to such links as 

 Enteropneusta, Chfetognatha, Amphioxus, Myxine, and other scantily 

 represented forms, they may be examples of degradation and not 

 " links " at all, but rather ends hanging loosely down from parts of the 

 cliain above them. In classification, above all other things, the maxim 

 should be, Festina lente. 



