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POPULAR SCIENCE REVIEW. 
gleaned from those of Cienkowski, Grreef, Hertwig, and a few 
other continental naturalists. From data supplied almost 
exclusively from these sources, he has constructed a compendium 
of Radiolarian characters, upon which he bases his revised classi- 
fication of this Order — an Order, let me observe, which, as now 
constituted, has only once heretofore been surpassed in the utter 
incongruousness of many of its elements — that is to say, in 
1838, when Ehrenberg, the great pioneer of our knowledge of 
the lower forms of animal as well as of plant life, whilst the 
microscope was as yet little more than a toy, published his 
magnificent work 44 Die Infusionsthierchen.” 
The names of a few British and American naturalists, accom- 
panied by a very incomplete list of their writings, are furnished 
at the close of Mr. Mivart’s memoir. As this, with one or two 
unimportant exceptions, is the only direct notice accorded 
them, it may be fairly inferred that his estimate of their labours 
on the Radiolaria tallies with that recently expressed by the 
late Director of the 44 Challenger” expedition ; namely, that 44 the 
Radiolaria which play so important a part in supplying the 
materials for new geological formations are not very, familiar to 
British naturalists.” * 
It shall be my endeavour to show, incidentally, in the course 
of the following remarks, that British naturalists have at any 
rate taken their fair share in the investigation, and have only 
acted with a commendable caution which might with advantage 
have extended further, in hesitating to devote their energies to 
the disentanglement of an assemblage of creatures which was 
day by day proving itself to be more thoroughly arbitrary. Mr. 
Mivart would seem, however, to be unaware that until a very 
recent date the Radiolaria, as recognized by the majority of 
British writers, comprised but four families, namely, the Actino- 
phryna , Acanthometrina , Polycystina , and Thalassicollidce ; 
that very detailed observations have been published by English 
writers on the morphological relations of each of these families ; 
and that it is to this hour an open, though I cannot believe a 
doubtful, question, whether the Radiolaria, as constituted by 
Haeckel and now revised by Mr. Mivart, ought to be retained 
as a Natural Order of the Protozoa, or abolished as being one 
which is purely artificial, misleading, and consequently worse 
than useless. 
Professor Haeckel is known by those who have read his works 
to be the unflinching advocate not only of the doctrine of Evo- 
lution in its most advanced sense, but of Spontaneous Genera - 
• “Voyage of the ‘ Challenger.’ The Atlantic.” By Sir C. Wyville 
Thomson, Knt., LL.D., D.Sc., F.R.S.S.L. & E., F.L.S., F.G.S., &c., Vol. i., 
p. 231. 
