352 
REVIEWS." 
Which of these diverse views should he adopted ? The choice 
perhaps lies between those of Professors Gegenbaur and Agassiz, 
and we feel on the whole disposed to give in our adherence to the 
latter, and to unite into one order the JPhanerocarpce , Charybdeidce , 
JEginidce and Lucernariadee . And for such a group the name* which 
Professor Agassiz has reserved appears sufficiently suitable, should 
we hesitate to adopt the still older designation of Medusce.^ As to 
the Lucernariadee , their close structural resemblance to the zooids 
of the hydra-tuba stock, from which the more common free-swimming 
Jdhanerocarpce are produced, together with the fact that, like the 
latter and the Charybdeidce , they possess the 5 gastric filaments ’ of 
which we have already spoken, must remove almost all doubts as to 
their true affinities. 
What, however, is to be done with the Cryptocarpce proper P 
Such of these as have been proved to be zooids must of course be 
relegated to the forms whence they originate. But there still remain 
behind Cryptocarpce of uncertain origin, along with those which 
undergo direct development. So long, indeed, as the LEginidee 
were retained in this division, it was possible to indicate two 
well-marked sections of the lower Medusae, founded on structural 
characters, which appeared to be correlated with others derived from 
supposed differences in their modes of development; the JEginidce 
being the direct produce of fertilized eggs, while the remaining 
Cryptocarpce were presumably zooids. But the LEginidce have now 
been removed, while doubts suggest themselves as to the zooid 
nature of, at least, three of the ordinary Cryptocarpce No one, 
however, regards the structural characters of such directly-developed 
Cryptocarpce as in themselves of ordinal value. And their different 
mode of origin is surely insufficient for this purpose. We do not 
place JPelagia apart from the other Lhanerocarpce , because a hydra- 
tuba stage is wanting in its development. And in various orders 
of animals, for example, the Trematoda , there are some forms which 
exhibit a singular metagenesis, while in others such phenomena do 
not occur. We are, therefore, disposed to side with Fritz Muller 
and Agassiz in their proposal to abolish the Cryptocarpce as a 
* In the best systematic work on the Annelids, that of Grube, the name Dis- 
cophora is given to the Leeches and their allies ( Hirudinea ). But this change in 
the use of a well established term is decidedly open to objection. 
j- Or Medusida. The restriction of this term, by Eschscholtz, to the Monos- 
tome Phanerocarpce, and by Huxley to the Cryptocarpce, has led in practice to some 
confusion. The genus Medusa of Linnmus (last ed. of Syst. Nat.) may fairly be 
taken as a synonym of Discophorce, Eschsch. And though this group has been at 
once diminished (by the removal of some Cryptocarpce) and increased (by the 
addition of the Lucernariadee) it still preserves so large a portion of its original 
contents as to remain, fundamentally, the same. Apart from historical consider¬ 
ations the name Lucernaridce (Huxley) would be a good one for this order, but is 
liable to be confounded with Lucernariadee, one of its families. 
J See the place assigned to these in the arrangement, already quoted, of Fritz 
Muller. 
