Differentiation. 289 



The Superior Thoracic artery arises from the axillary artery, or some- 

 times from the acromial a branch of the axillary. It sends numerous 

 branches to the Pectoralis Major and P. Minor muscles. " In some 

 subjects there are two or three external superior thoracic arteries.'' 

 ( Med. Die. ) The external mammary arteries vary in number, usually 

 four, according to Neil and Smith, and they arise singly or together 

 from the axillary artery. ( They are not particular. ) 



The mastoid artery (branch of carotid) is irregular and uncertain in 

 its origin. It supplies the muscles and glands of the neck. Nerves too: 

 Thus the anterior ( efferent ) nerves of the first cervical pair are some- 

 times absent. In this case there is a supply of fibres from the spinal 

 accessory or the hypoglossal, or both. ( Carpenter s Physiology, 461-) 



Case of deficient brain: The middle part of the fornix and all the 

 septum lucidum wanting, and the corpus callosum reduced to a mere 

 rudiment one-fourth of an inch long. The person was defective in fore- 

 thought, &c. , but was as intelligent as the average. ( Carpenter ) (For 

 description of these parts see chapter on Brain. ) The carotid nerve 

 sometimes forms a small gangliform swelling on the under part of the 

 artery in the cranium, called the ganglion of Laumonier. Accessory of 

 parotid gland sometimes connected with parotid, sometimes not. Fora- 

 men ccecum sometimes found in the ethmoid bone and admits a small 

 vein from the nose. (Neil and Smith, 29 Anatomy.) Ethmoidal ar- 

 teries are two in number the anterior arises from the ophthalmic ar- 

 tery, the origin of the other varies. 



There are considerable variations in the muscles of the face. ( See fig. 

 60. ) The zygomatic minor is often wanting, and its lower terminus, or 

 insertion in the upper lip, is often abolished and the insertion made in 

 the fascia of the cheek or in the zygomatic major. Not unfrequently 

 the muscle is double. The z. major, too, is sometimes double, and in 

 other cases wanting altogether. The risorius, or laughing muscle, is 

 also often absent, and so is the pyramidalis, which draws up the skin 

 of the nose. The variations in these muscles must cause variations in 

 the expression of the same emotional states. 



Supernumerary nipples are of rather frequent occurrence. Their 

 usual situation is below and toward the middle from the normal nipple, 

 but sometimes they are above and outside, and occasionally they are 

 found on the abdomen. As a rule the left breast is more developed 

 than the right, and the extra nipple, when there is one, occurs on the 

 left side oftener than the other. This is accounted for from the cir- 

 cumstance that the left nipple is used more than the other beoause the 

 child is carried on the left side so as to leave the right hand of the 

 mother free. Moreover, when a nipple, or mammary gland, is inisiing 

 or defective, (amastia) it is usually the right one. In 104 females, 



