PROF. AGASSIS S 



tton that they do cot belong to the family of Lep- 

 idoptera. 



I see the time will not allow me to go through 

 the whole o? this extensive subject - T so that I shall 

 call your attention again in my next lecture to the 

 transformation of structure which takes place in 

 these animals. Let me only make one remark 

 more with reference to the relative position of the 

 various families of the numerous order of insects, 

 and to the relative value of their distinguishing 

 character. Why should we be led to arrange the 

 insects and articulated animals in a natural order, 

 by other considerations than those derived from 

 their own mode of growth ? For, if we find that in 

 insects the earliest period of life is that of the car- 

 nivorous animals, let that be the lower condition 

 for articulated animals. And if we see that they 

 successively undergo changes, in which, growing 

 to our eyes to more perfect animals, they finally 



assume the structure of seeking insects, than let 

 us consider the condition of sucking insects the 

 higher condition. And let us no longer transfer 

 our impressions from one department into the other. 

 The same difficulties occur really in all other 

 classes. Because the Carnivora among Mammalia,, 

 come so near to the Monkey, and thus approach to 

 the affinity which raises the Monkey next in rank 

 to man, it is no legitimate consequence, that the 

 Birds of Prey should be the highest. Nor does it 

 prove that the carnivorous fishes should rank high- 

 er than the others : and still less, does it follow, that 

 the chewing insect should take the highest rank, 

 especially when we see that the ehewiag condition 

 is the lowest embryonic condition of their life* 

 And tet us, in future, arrange insects according to 

 the rale of insects, and not according to tie struc- 

 ture of other animals. 



LECTURE VII. 



Before entering upon the proper subject of this 

 evening's lecture, I have to mention a few facts 

 which I have ascertained upon the growth of some 

 Polypi (or rather Medusae, if Tubularise have to be 

 considered as Medusae) which I consider so highly 

 valuable as to deserve really to call our attention 

 for a few moments. I have received from Mr. 

 Hawks, of the Navy Yard in Charlestown, a bunch 

 of Polypi, taken from the bottom of a ship which 

 has been lying for three months and a half in the 

 harbor. When she was launched, on the 14th of 

 September last, she had, of course, none upon her. 

 She had been lying in the water from the 14th of 

 September to the 28th of December, when she was 

 taken into the dry dock. During this time, the 

 bottom of this ship has been covered with the most 

 astonishing, the most luxuriant growth of Polypi 

 which can be imagined. Thousands and thousands 

 of Polypi stems, as long as five, or six, or seven 

 inches, forming the most beautiful flower garden, 

 upon the bottom of the vessel. And not only have 

 all these Polypi grown to this size, but they have 

 branches, and these branches these secondary 

 branches have given rise to branches of a third 

 order, in this short time. Now, the question is, how 

 can these innumerable stems have grown upon 

 this vessel ? They could not have been attached 

 to it accidentally, as Tubularise, in their ordinary 

 growth, are always attached, and when freed, fall 

 to the bottom, without having the means to move 



about. The uniformity of their growth, shows thai 

 they have grown upon the vessel from a uniform 

 starting point, not from a certain number of 

 stems which had accidentally become attached to 

 the vessel ; all of which must be supposed in the 

 same condition, in the same state of growth, when 

 they became attached, and that they have grown 

 upon this vessel naturally, uniformly, up to the 

 present day, or rather up to last week. But to be 

 attached there, in such a manner, not accidental- 

 ly, thev must have been free ; and it is just a point 

 to which I alluded in a former lecture, whether 

 Tubularise had or not, a free generation, alter- 

 nating with their fixed growth. A free generation 

 among them is not known ; yet I inferred from 

 some data, that the affinity of Tubularise with Me- 

 dusse was very close, and I ventured even to predict 

 that some one of the small free Medusae of Boston 

 harbor might be their free form that a free gen- 

 eration might be found. 



Now, the circumstances above stated, show that 

 there must be a free generation of Tubularise,which, 

 by the 14th of September, or some time later, were 

 swimming in Boston harbor in countless num- 

 bers, and attached themselves to the keel of that 

 vessel, and grew there to form these innumerable 

 stems. Whether this growth is immediately de- 

 rived from the germs, which are produced in the 

 bunches, which are known to exist in Tubularise, 

 or whether it is only another generation, derived 



