1 877-] 
and the Evolution Hypothesis. 
521 
flagellum (closely resembling a spermatozoon) absorb 
another monad prior to muliplication. This corresponds 
exactly with the union of the sperm-cell and the germ-cell 
in the fecundation of the ovum.* 
Having briefly traced some of the reversions to lower 
types in the higher organisms, I shall now quote a few inte- 
resting notes on the individual development of the lower 
animals and of plants, from Oscar Schmidt’s “DoCtrine of 
Descent and Darwinism.” He remarks that “ The circum- 
stances of parasitic worms are repeated by the parasitic 
Crustacea, as, moreover, a probably primordial form of the 
crab family is preserved in the metamorphoses of several 
orders of this large and diversified, though coherent, class. 
The larva which, it may safely be assumed, approximates 
closely to the primordial form, was at one time taken for an 
independent genus, and received the name of Nauplius. 
Hence a Nauplius phase is spoken of which obtains espe- 
cially among the lower Crustacea, the Copepoda, parasitical 
Crustacea, and Cirripedes, and the remarkable Rhizopoda 
connected with them ; but is not wanting in the highest 
order, the decapodous stalk-eyed crab. We shall later have 
to make acquaintance with the so-called curtailed develop- 
ment which among the crabs has been adopted by the 
decapods, and it was formerly supposed by all. Were this 
actually the case we should still, by analogy, infer their 
connexion with the orders repeating the Nauplius phase in 
the course of their development ; but it was a welcome dis- 
covery of Fritz Muller’s that a shrimp (Peneus) still begins 
its development as a Nauplius, whereas all the other mem- 
bers of the order, as far as they are known, leave the egg 
in the higher Zoea phase. As of the hundreds of stalk- 
eyed crabs scarcely a dozen have hitherto been examined as 
to their development, it will not be doubted that, with 
regard to the Nauplius phase, some resemble the Peneus of 
the Brazilian coast. But even were this case to prove 
unique in the order, it would suffice as a living witness to 
the connection between the presence of the decapods and 
the primordial crabs. There can be no other view of the 
subject. The Nauplius phase in the development of the 
Peneus is either a shining testimony in favour of the doc- 
trine of Descent or a senseless paradox.” Again : “ The 
shell of the individual Ammonite begins with the old mor- 
phological type, and then adopts the modifications in the 
same order in which they follow in vast periods in the 
* This would seem to indicate that the distinction of sex is coeval with life 
itself. 
