ZOOLOGY: E. B. WILSON 
321 
THE DISTRIBUTION OF THE CHONDRIOSOMES TO THE 
SPERMATOZOA IN SCORPIONS 
By Edmund B. Wilson 
DEPARTMENT OF ZOOLOGY, COLUMBIA UNIVERSITY 
Read before the Academy. April 17. 1916. Received April 29. 1916 
The spermatozoon carries into the egg two kinds of bodies both of 
which have been supposed to play a definite part in heredity; these are 
the chromosomes and the chondriosomes, the former belonging to the 
nucleus, the latter to the protoplasm or cytoplasm. If these bodies 
are in fact concerned in heredity we should in general expect them to 
be equally distributed to the germ-cells by means of division or some 
similar process of equal allotment; and as far as the chromosomes are 
concerned such is always the fact, except in case of the sex-chromo- 
somes. ^ The chondriosomes, too, are distributed with approximate 
equality in many cases, but whether they are comparable with the 
chromosomes in this regard has not yet been certainly determined. I 
have for some time been engaged with a study of this question in two 
species of scorpions in both of which the phenomena are displayed with 
almost unexampled clearness, and which seem to give a conclusive re- 
sult on this point. It is in some respects a surprising one. 
The two species in question are 0 pisthacanthus elatus (Gervais) from 
Southern California and Centrums exilicauda (Wood) from Southern 
Arizona.* In the latter, alone among animals hitherto examined, it is 
possible to conclude with certainty that the chondriosome-material is 
divided with exact equality among all the spermatozoa. The defi- 
niteness of this result is owing to the unique fact that before the matura- 
tion-divisions take place the whole of the chondriosome-material in 
the primary spermatocytes is concentrated in a single ring-shaped 
body which is then equally divided in such a way that each spermatid 
receives one-quarter of the products, the process taking place with a 
precision that is comparable to that seen in the distribution of the chro- 
mosome-material. The body in question represents a hitherto un- 
described type of chondriosome. It arises from numerous minute 
mitochondria or chondrioconts which early in the growth-period of 
the spermatocytes become concentrated to form a large, homogeneous 
and sharply defined ring, lying in the protoplasm and surrounding the 
idiozome near one pole of the nucleus. Persisting unchanged through- 
out the growth-period this body places itself Hke a heterotype chromo- 
*My thanks are due to Nathan Banks, Esq., for an authoritative identification of the 
species. 
