THE THRESHOLD OE EVOLUTION. 
151 
their highest stage of development, consist merely of small 
pieces of structureless plasson or slime ; ’ and that ‘ the whole 
body consists merely of plasson’ (Op. cit. vol. ii. p. 43.) 
Let us see how these remarkable statements tally with the 
history so circumstantially recorded by Hoeckel of two of his 
typical Monera, Protomyxa aurantiaca and Myxastrum radiate* 
It is almost superfluous for me to mention that in the earliest 
period of independent existence of nearly all the Protozoa 
holding higher rank than the Bhizopoda, there occurs an 
Amoeboid stage, which is transitory and followed by the other 
developmental phases constituting the life-cycle of these 
organisms. Haeckel, on the other hand, draws the primar}^ 
characters of his Monera — those characters upon which he bases 
the assertion that they are the simplest conceivable organisms 
— on the appearances presented by only one out of several 
phases through which they pass. 
After premising that he is about to restrict himself entirely 
to 4 true Monera, i.e. naked protoplasmic bodies without nuclei,’ 
and means to pay no attention to the Protoplasta distinguished 
by the possession of one or more nuclei (as Amoeba and Arcella), 
‘ or to the Phizopoda , distinguished by the possession of a distinct 
shell or membrane we have presented to us a figure of the 
Amoeboid ‘ full-grown fasting ’ stage of Protomyxa aurantiaca 
(See Plate iv. fig. 4), an organism detected by Haeckel upon 
a Spirula shell in 1866 at Lanzarote, one of the Canary Islands. 
Its red colour he regards as distinguishing it from other 
Monera. He traced it through the following distinct successive 
stages. The first, that of ‘a minute tolerably opaque red ball, 
covered with a thick , structureless membrane nevertheless, sub- 
sequently found to consist of ‘several concentric layers/ The 
orange-red ‘contents of the balls appeared as a thoroughly 
homc)Geneous obscurely granulated mass , in ichich might be ob- 
served very numerous exceedingly fine particles and a small quantity 
of strongly-refracting red grains .’ (Plate iv. fig. 5.) Certain 
indentations on the surface of some of the balls proved to be 
the external sign of the breaking up of the whole cell-contents 
into a great number of smaller balls. In some of the balls 
which were kept under observations in watch-glasses filled with 
sea-water, the orange-red plasma divided as before into a number 
of smaller red balls. (Figs. 6 and 7.) But this division did 
not stop with a repeated bipartite division within the larger cell 
* I purposely leave out of consideration Hmckel’s Moneron Protogenes 
pnmordialis, as lie admits it to be very closely related to Amoeba porrecta of 
Schultze ; adding that as the history of its mode of development and repro- 
duction icas unknown to him, he could not describe its affinities. There can 
hardly be any doubt as to its being Scliultze’s A. porrecta. Of Batlujbius as 
a Moneron nothing need be said. 
