1891.] Zoology. 495 
; EXPLANATION OF FIGURES. 
FIGS. 1 and 2 are drawn to the same scale. Figs. 2 and 3 are drawn to 
a scale a little larger than 1 and 4. 
Fic, 1.—Section through body of embryo of black snake, in front of the 
cloaca. 
Fic. 2.—Portion of Fig. 1, to right of line 1-2, drawn to larger scale. 
FIG. 3.—Right penis of black-snake embryo, two weeks older than Fig. 1. 
Section passes through body just behind the cloaca. 
Fic. 4.—Section of left penis of black-snake embryo, one week older 
than Fig. 3. Section taken just behind cloaca, 
P, ridge which marks first appearance of penis; c4, notochord ; a, dorsal 
artery; w, wolffian duct; d, alimentary canal; a, mesoderm; æ, stratum 
mucosum ; c, stratum corneum (not figured in 1 and 2); 7, retractor muscle ; 
$, beginning of anal sac; , blood spaces forming in the mesoderm; 4, 
edge of posterior wall of cloaca. 
The Quadrate Bone.—R. Broom thinks? that all previous mor- 
phologists have been in error in trying to recognize the quadrate 
among the bones of the middle ear of mammals. He thinks it forms 
the articular cartilage. 
“Some of the Causes and Results of Polygamy Among 
the Pinnipedia.’’—In the February number of the AMERICAN NAT- 
URALIST (Vol. XXV., pp. 103-112), Mr. C. C. Nutting has published 
some interesting notes on sexual disparity among polygamous seals, 
and deductions from the observations recorded. Mr. Nutting, how- 
ever, was not the first to draw attention to such facts and the princi- 
ples involved. Over twenty years ago (January, 1871) the subject was 
noticed, and the resulting conditions tersely formulated in the AMERI- 
CAN Naturatist (Vol. IV.). In a review of Mr. Allen’s then recent 
memoir on the eared seals I published the following paragraph 
immediately after one on the genetic relationships of the families of 
innipeds : 
“ In this connection it maybe recalled that while in the monoga- 
mous Pinnipeds, or those living in small communities, there is little 
difference in size between the males, in the social species, or rather 
those of which the males have harems, the males are vastly larger than 
the females. Macrorhinus, of the Phocids, and all the Otariids belong 
to the latter category. The difference between the sexes would be 
readily explained by Mr. Darwin on the principle of natural selection. 
It is evident that the larger and more vigorous males would be the 
eventual possessors of the females, and the disproportion of the sexes 
7 Ann, and Mag. Nat. Hist., VI., 409, 1890. 
