PROGRESS OF ZOOLOGY. 
34 7 
saurians, but the Branchiostoma is as indefinable for scientific 
purposes as any of the cattle of fairyland. There is cer¬ 
tainly room for an artificial system of zoology of a com¬ 
prehensive kind for the tabulation of the entire animal 
kingdom. 
Looking at the several departments of zoology in their 
present aspects, it is evident that the most satisfactory pro¬ 
gress has of late years been in the study and classification of 
the lower forms of life. The aquarium and the microscope 
have given an impetus to the study of the Invertebrata, and 
such immense additions have been made to the knowledge of 
this great section that the mere weight of facts threatens to 
separate it from the hitherto recognised connection with the 
vertebrates, and so to constitute in zoology two distinct 
sciences, the future paths of which will be separate though 
•parallel. It is in this section that we have most striking 
evidence of the abundance of life in every region of the 
globe. Dr. Wallich and Mr. Gwyn Jeffreys have, by their 
researches on the subject of deep-sea life, enlarged immensely 
the geographical limits and the physical conditions known to 
be favorable to the production of animal life. In that still 
lower department of the Infusoria, the magnificent work of 
Pritchard offers another example of the splitting up of old 
divisional arrangements through the accumulation of facts 
indicative of distinctive characteristics. The publication of 
a fourth edition of this work, combining the labours of 
Arlidge, Archer, Ralfs, Williamson, and Pritchard, with the 
magical delineations bv Mr. Tuffen West,* is a sufficient 
proof that natural history flourishes in Britain, and that the 
objects least attractive to the popular eye are acquiring a 
popularity such as to assure us that the cultivation of 
science is almost universally shared in by the intelligent 
classes of this country. But when we get among desmids 
and diatoms we have almost done with zoology, and we may 
take advantage of this extremity to offer a few remarks on 
the higher forms of the vertebrata. 
If we are astonished at the abundance of life on the globe, 
and can sympathise with Dr. Livingstone’s remark, that it 
“ seems like a mantle of happy existence encircling the world,” 
it is also pretty certain that some of its forms are fast pass¬ 
ing away from us, and that not very far in the future the 
zoologist will pay as much attention to mammals recently 
extinct as we do to certain fossil forms, because they fill up 
* i A History of Infusoria, including the Desmidiacese and Diatomacese.* 
By Andrew Pritchard. London: Whittaker and Co. 
