528 MR. G. J. BOMA^'ES ON SOME NEW SPECIES, VARIETIES, 



selves both as abnormal multiplications and abortions of parts. 

 In all the cases of asymmetrical multiplication which I observed, 

 the peculiarity was confined to the lithocysts, and always showed 

 itself in the same manner. That is to say, I have several times 

 observed, in otherwise normal specimens of A. aurita, the 

 presence of nine instead of eight lithocysts; and in all these 

 cases the supernumerary lithocyst, which was always fully formed 

 and provided with the usual hood, was placed beside and in 

 close contact with one of the normal lithocysts. This latter fact 

 appears to me important when considered in relation to the 

 theory of Pangenesis ; for upon this theory it would follow that 

 if a supernumerary lithocyst is to be developed at all, we should 

 expect it to be developed in apposition with one of the normal 

 lithocysts rather than in any other position. Our ground for 

 expecting this is, of course, that the theory of Pangenesis sup- 

 poses similar gemmules to have a mutual affinity for one another ; 

 and as lithocyst-gemmules would naturally be plentiful in the 

 region of any normal lithocyst during the process of its develop- 

 jnent, or of its repair if injured, if any thing went slightly wrong 

 in either of these processes, facilities would be offered for the 

 adhesion of improper gemmules at the point where the dis- 

 turbing cause acted ; and these improper adhesions having once 

 taken place and being then followed by normal adhesions of 

 proper gemmules, the result would probably be a duplex organ. 



I have said that in all the cases of asymmetrical multiplication 

 of parts which fell under my notice it was the lithocysts alone 

 that were affected. But besides these cases of asymmetrical 

 multiplication of parts in Aurelia, I saw several instances of 

 strictly symmetrical multiplication ; and in all these instances 

 every part of the organism was equally, or rather proportionally, 

 affected. That is to say, as in the single instance of multipli- 

 cation of parts which I observed in Sarsia, all the organs of 

 the nectocalyx (eye-specks, tentacles, and nutritive tubes) were 

 similarly affected, so in the several instances of multiplication of 

 parts which I observed in Aurelia, all the organs of the umbrella 

 were similarly affected. If any one will turn to the admirable 

 plates contained in Professor L. Agassiz's third contribution to 

 the Academy of Arts and Sciences, and representing a normal 

 specimen of the genus Aurelia, he will see that the nutritive 

 canals bear a very definite and symmetrical arrangement with 

 reference to one another, and also with reference to the ovaries 



