DEVELOPMENT OF QUADRUMAXA. 745 



tomatose, non-coherent : the foetal processes penetrate cavities in 

 the decidua apparently homologous with the utriculi of the 

 human uterine lining, and having as little the structure of true 

 follicular glands. The original deciduous capsule of the ovum is 

 reduced to a very thin layer of mucous substance, exterior to 

 the placental zone. 



Seals have rarely more than two young, and more commonly 

 but one, at a birth. In the latter case the fcetus and its mem- 

 branes are limited to one horn of the uterus, not extending into 



o 



the opposite horn, as in Cetacea. The placenta is zonular, in 

 four or five continuous or connected divisions. In Phoca vitulina 

 the diameter of the zone parallel with the long axis of the ovum 

 is between two and three inches. In parturition the sclerous 

 tissue of the symphysis pubis becomes relaxed, allowing divarica- 

 tion of that part of the pelvic arch, which, consistently with the 

 reduced hind limbs, is smaller than in land Carnivores. 



The gestation of the Bear ( U. americanus) is seven months : 

 the young, usually two in number, are born as well shaped as in 

 other Carnivora, but are more naked : the eyelids are closed, and 

 so continue for about four weeks. From some information I 

 hare received respecting the Badger, it would seem, like the 

 Hoe, to have a long gestation in proportion to its size. The 

 young, as with the Bear, are blind at birth. 



405. Development of Quadrumana.- -The Makis (Lemtir) have 

 sometimes one, commonly two, rarely three young at a birth. A 

 pair of the Lemur albifrons, captive at the Jardin des Plantes, 

 Paris, copulated December 23, and afterwards repeatedly for five 

 or six days : the female brought forth April 13, after a gestation 

 of fifteen weeks. The neAV-born young was covered with very 

 short hairs, and had its eyes open. 1 



The Marmosets (Hapale Jacchus) resemble Lemur in the 

 number of young : the gestation is three months : the young is 

 naked at birth, except upon the head, and gets clothed in three 

 or four weeks. In Callithrix sciureus the long twisted umbilical 

 cord is chiefly in connection with a circular thick discoid placenta : 

 but some of the branches of both the two arteries and two 

 veins extend (as it seemed to Schroeder von der Kolk) 2 to a 

 smaller and thinner circular villous tract, like a second placenta 

 at the opposite end of the chorionic sac. 



The Howler (Mycetes seniculus) has a single placenta, also 

 circular, discoid, from which the foetal blood is returned by two 



1 CCLXXYII". p. 50. 



2 Ib. p. 55, pi. 6, fig. 1. Eudolphi found the placenta single in Hapale Jacchus. 



