Or 
(op) 
ETHEL BROWNE HARVEY 
III. HISTORICAL AND CRITICAL 
The first attempt to count chromosomes in the Metazoa was 
made in 1878 by Selenka, in his “ Befruchtung des Kies von Tox- 
opneustes.”’ He gave the number in the cleavage cells as vary- 
ing between 14 and 24, a rather wide range and not very close to 
the mark (36). Retzius? in 1881 gave the number for Triton 
punctatus as between 12 and 16 in the somatic cells, also some- 
what far from correct (24). The next observation, by Flemming? 
on the salamander in 1882, was accurate and correct, and to him 
therefore belongs the credit of establishing a definite number of 
chromosomes for a definite species. He was also the first to at- 
tempt a count on human cells, given in the same publication. 
Very shortly after this, Strassburger,‘ 82, gave definite and cor- 
rect numbers for several species of plants. Then came three 
papers giving the chromosome numbers in Ascaris, Anton Schnei- 
der’s ‘Das Ei und seine Befruchtung’ in 1883, Nussbaum’s® 
paper in 1884 and the very thorough and brilliant work of Van 
Beneden® which was published in 1883, although it did not ap- 
pear till April 1884. Soon after, still in the ’80’s, came Carnoy’s 
and Boveri’s papers on the nematodes and other works on the 
nematodes, molluscs and vertebrates. Since then, chromosome 
counts have been made by many observers on about 960 different 
species of animals. 
Several lists of chromosome numbers have appeared previously, 
the first by Wilson in ‘The Cell’ in 1900, a partial list which in- 
cluded about fifty species of animals and a few plants. In 1905, 
Enriques’? gave an incomplete list of numbers in animals, ex- 
pressing the different numbers in mathematical formulae, as 
powers of 2 and 3. Montgomery* in 1906 gave a list which was 
supposed to be very nearly complete, but there are many omis- 
sions and a good many inaccuracies in the list. Montgomery’s 
2G. Retzius. 1881. Biol. Untersuchungen, p. 109. 
3W. Flemming. 1882. Arch. mikr. Anat., 20, p. 1. 
4K. Strasburger. 1882. Arch. mikr. Anat., 21. 
5M. Nussbaum. 1884. Arch. mikr. Anat., 23, p. 155. 
6 —. Van Beneden. 1883. Arch. de Biol., 4, p. 265. 
7 Paolo Enriques. 1905. Archivio di Fisiologia, 2, p. 258. 
8T. H. Montgomery. 1906 Trans. Amer. Philos. Soc., 21, p. 97-162. 
