"runlli. Fi^b.1?i«7a '] ^oyal Microscopical Society. 93 



harmony i^ervacling tlie character of the ccenenchyma and the form 

 and disposition of the individual polyp-cells throughout the entire 

 group which may possibly warrant their eventual arrangement 

 under one generic title. In illustration of the small value of 

 general external form for the purposes of even specific diagnosis, 

 as applied to the " hard structures " of the Coelenterata, I need 

 only refer to Millepora alcicornis among the Madrejjores or " Stony 

 Corals," in which the amount of variation of the external contour 

 of its corallum is simply perplexing; the most striking examples 

 of these, taken separately, might be almost supposed to represent 

 distinct genera, but the existence of intermediate conditions inti- 

 mately uniting the whole series unquestionably substantiates their 

 specific identity. 



The facts which have been ehminated in the foregoing remarks 

 will, I think, suffice to demonstrate beyond doubt what a highly 

 important element the Calcareous Spicula represent in our appre- 

 ciation of the generic characters of the Gorgonidee. The study of 

 the group from this point of view must, however, be considered 

 quite in its infancy; but the time has arrived when zoologists must 

 no longer be content with the characters aflbrded by general contour 

 or by the examination of the dried poly paries only. Not only is it 

 necessary that the spicula alone should again be studied; our 

 information respecting the variations in form of the polyp-animals 

 themselves is as yet of the most meagre description ; and until we 

 have learnt to appreciate these characters by the examination of 

 the animals preserved in spirit, or, what is more important still, 

 alive in their native element, we can scarcely expect to arrive at 

 a just estimation of their true zoological aflfinities. 



Further particulars respecting the specific variations of the 

 spicula, the position the different forms occupy in relation to the 

 common polypary, and the general law of affinity which undoubtedly 

 pervades the whole series, must necessarily form the subject of a 

 future communication. 



In conclusion, I must not neglect to testify to the good work 

 our trans-Atlantic cousins are achieving in this direction by fitting 

 out expeditions, for the main purpose of exploring and arriving at 

 a better knowledge of the representatives of the Marine fauna 

 on the other side of the Atlantic ; * an example, which it is a 

 pleasure to be able to add, the British Government has at length 

 recognized the high importance of following ; and in fact if 

 England is (and may such be her ever happy destiny) to remain 



* The names of Prof. A. E. Verrill and Count Pourtales are particularly 

 worthy of notice for having contributed so richly to our knowledge of the Ccelcn- 

 terata. Many new genera and species of Gorgonaccce have been described by 

 them ; but want of space necessarily obliges me to postpone entering on the present 

 occasion into the results of their investigations. 



