No. 387.] REVIEWS OF RECENT LITERATURE. 259 
the central spindle during division as in Noctiluca and many Meta- 
zoa. A distinct centrosome was found only in Noctiluca. The 
nuclei of most Protozoa belong, however, to aberrant types, which 
seem to have developed along divergent paths and only remotely 
resemble the more primitive forms on the one hand and the higher 
forms on the other. Examples of these aberrant types are found in 
Ameba proteus, Ceratium, Noctiluca, and the Infusoria in general. 
Chromosome formation is first seen in flagellates in the form of rods 
which arise by the union of the scattered chromatin granules. They 
form in the typical, though primitive, metazoan manner in Noctiluca 
and Euglypha, and all metazoan cells pass through these stages in 
preparing for mitosis. CAK. 
The Plotting of Biological Data in which it is necessary to 
exhibit an enormous range of numbers, as, for example, in certain 
lines of plankton work, presents a practical difficulty which may be 
obviated by a simple method suggested by Mr. D. J. Scourfield.' 
This is the use of logarithmically ruled paper, or of ordinary cross- 
section paper by the assignment of suitable values to the lines. 
Thus millimeter paper may be used if the centimeter lines are held 
to represent 1, 10, 100, 1000, etc., and the intermediate millimeter 
lines are given the numerical values whose logarithms are o.1, 
0.2, 0.3, 0.4, etc. For ordinary biological data, logarithmic ruling in 
one direction only is required, though for certain problems, e.g., 
the plotting of variations of a rapidly increasing number of organ- 
isms, paper ruled in this manner in both directions might be used. 
This method of graphic presentation of biological statistics has the 
additional advantage of exhibiting proportionate changes in numbers 
by lines having the same angle of slope wherever situated in the chart. 
CAK 
ZOOLOGY. 
Relationships of North American Grouse and Quail. — Dr. H. 
L. Clark has just published one of his useful papers on the feather- 
tracts of birds ; in this case on those of the North American grouse 
and quail. The work of Nitzsch is thus carried on and * extended, 
1 Scourfield, D. J. The Logarithmic Plotting of Certain Biological Data, 
Journ. Quek. Micr. Club, Ser. II, vol. iv (1897), pp- 419-423, Pl. XX. 
2 Clark, Hubert Lyman, Ph.D., Instructor in Zoology, Amherst College. The 
