REVIEWS. 
ipsa 
Tue POPULAR Science Review. London (Quarterly). 
The October number contains a very valuable and beautifully illust z 
ted article on the Microscope in Geology by David Forbes, of which we 
make use on another page. — Dr. M. T 








- growth in the leaf itself, is the most important, and probably the only 
one of itself sufficient to produce the result.” This new growth is 
thus described from Von Mohl’s account. “ Shortly before the fall of 
the leaf, there begins to be formed a very delicate layer of cells, 
growth of which is from above downwards, so that, beginning 
the axillary side of the leaf, and gradually extending downwards and 
outwards, nearly at right angles to the long diameter of the cells of the 
leaf stalk, at any rate at right angles to the plane of the leaf, it ef 
a gradual separation between the stem and the leaf, as effectually 
knife would do.” These changes of tissues and consequent fall of 
leaf are not wholly due to a change of seasons “ from wet to dry, or 
hot to cold, for it not unfrequently happens that if a tree be stri 
of ‘its leaves in summer, it forms during the autumn new ones, W 
remain on the tree during the greater part of the winter, or at any 
until long after the usual period.” 
Dr. E. R. Lankester gives a very useful article, well illustrated, on 
Flat-worms or Planarians. The subjoined table* presents the la 
views as to the classification of Worms taken from Peter’s and Ca 
SE POM ol ADETA AA ETE E E 

*A TABULAR VIEW OF THE CLASSES AND ORDERS OF VERMES. 
Sub- Vermes. 
Class I. Annulata (Ringed-worms). ‘ 
; Orders: Polychaeta (Marine), 
(Land and Fresh-water). 
Discophora (Leeches). 
Class II. Gephy esha ag ii k 
én Tahi 5 + 

Orders: Sipunculus, etc. 
Class III. Rotifera (connected to Arthropods and Turbellaria). 
Orders: Cephalotricha (Wheel-animals). 
pe ews: and Nemertians). 
ematodes (Flu King’s Yellow-worms 
Cestodes (Tape-worms). e 

