DEPARTMENT OF EMBRYOLOGY. 99 



monkey, which, besides placing this new and rare material on record, 

 throws additional light on the laws of growth in primates. On com- 

 paring the two alouatta fetuses with human fetuses of corresponding 

 stages of development, it is found that they differ in the following 

 points: In the alouatta the trunk is more slender, the shoulders, 

 nipples, and umbilicus are situated higher, the upper extremities are 

 relatively longer, the hand and foot very much longer, and the thumb 

 and great toe shorter; the brain part of the head is smaller, especially 

 in height, the nose is hgher, and the ear larger. During development 

 the forearm of the alouatta grows faster than either the upper arm or 

 the hand; likewise the lower leg has a greater rate of growth than the 

 thigh or foot. As a whole, the lower extremity grows more rapidly 

 than the upper one. The relative length of the fingers and toes 

 remains unchanged during development. The relative size of the 

 brain part of the head decreases, whereas, that of the face part re- 

 mains constant during growth. As regards the different portions of 

 the spinal column, the relative length of the thoracic region decreases, 

 while that of the lumbar, sacral, and caudal regions increases. Of 

 special interest in the skeleton of the alouatta is the forking of the 

 manubrium sterni into two diverging processes, due to the enormous 

 development of the hyoid, a condition which is pronounced even in 

 the fetus. The foramen zygomatico-temporale, a remnant of the 

 former complete communication between orbital and temporal fossae, 

 is of considerable size in the fetal skull. 



The rare circumstance that the two alouatta fetuses were single- 

 ovum twins afforded an opportunity to test the frequently asserted 

 "identity" in such twins. It was found that on an average a given 

 measurement differed in the two fetuses 4.81 per cent. 



In a third paper Dr. Schultz describes the occurrence of a sternal 

 gland in the fetal and adult male orang-utan. In the middle of the 

 chest, at the level of the nipples, is a pit-hke depression in the skin, 

 which is the outlet for numerous unusually large sebaceous glands 

 conglobated beneath. This sternal gland occurs in but a small per- 

 centage of female orang-utans and is relatively larger and more 

 conspicuous in male fetuses than in the old animals. The pit may 

 reach a diameter of 2.5 mm. and a depth of even 3.5 mm. At times 

 it is surrounded by a low circular wall or, especially in later life, by a 

 dark brown pigmented zone. This gland in primates seems to be 

 restricted to orang-utan; an analogous gland, however, has been 

 observed in some chiroptera and marsupials. 



