No. 4. — CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY 
OF THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE. E. L. MARK, DIRECTOR. No. 188. 
The Heredity of Sex. By W. E. CASTLE. 
CONTENTS. 
PAGE PAGE 
i Infroduction «..< ... . », 189 (5) Special cases . . . . 201 
II. Sex an attribute of each ga- A. Rhodites rosae . . 201 
mete, and hereditary 190 B. Hydatina senta . . 202 
III. Principles of heredity appli- C. Artemia salina .. . 2038 
cablesto'sex) i .- = 191 D. Exceptional parthe- 
1. Mendel’slaw .. . 191 nogenesis in Bombyx 
(a) The principle of domi. mort, ef. 1/36". 3.208 
Hance a. 191} V. Abnormal sex proportions 
(b) The principle of segre- among hybrids . . 205 
g@ationy, “ta. |: . 192 1. Relative infertility of cer- 
2. Mosaic inheritance . . . 192 tain combinations of 
IV. Application of the principles gametes... 206 
BtRted 65.5. 193 2. Coupling of certain sex aiid 
1. Dioecious and ReniNphne: somatic characters in 
dite organisms . . 193 the germ-cells . . . 208 
2. Parthenogenetic organisms 198) VI. Summary ...... . 214 
(a) General application . . 198| Bibliography. . .... . . 216 
I. Introduction. 
A NEw theory of sex is advanced in this paper, yet a theory which in 
its elements is not new. It is an attempt to correlate three ideas, the 
correctness of which, separately considered, is generally recognized : 
(1) the idea of Darwin (76), that in animals and plants of either sex 
the characters of the opposite sex are latent ; (2) the idea of Mendel 
(66), that in the formation of the gametes of hybrids a segregation of 
the parental characters takes place, and when in fertilization different 
segregated characters meet, one will dominate, the other become latent 
or recessive ; (3) the idea of Weismann (’93) that in the maturation of 
egg and spermatozoon, a segregation of ancestral characters takes place, 
and that this segregation is attended by a visible reduction in the num- 
ber of chromosomes in the germinal nuclei. 
VOL. XL. — NO. 4 
