204 ANATOMY OF VERTEBRATES. 



does not admit of the distinction into external and internal ; it 

 proceeds snperficially along the side of the neck in company with 

 the par vagum. The vein of the right side exceeds the other in 

 size ; it is often twice as large. The jugnlar vein receives several 

 lateral branches from the muscles and integuments of the neck, 

 ib. d, the oesophagus, &c. (the veins from the crop joining the 

 jugular are shown at c) : one of these near the head is much 

 longer than the rest, ib. e ; it lies deep amongst the muscles, and 

 appears to communicate with the vertebral vein. There is a 

 branch of the jugular which goes to the superior larynx amongst 

 the muscles of the tongue and of the hyoid, and another for the 

 muscles within the jaws and the integuments in the back of the 

 mouth ; these might be called the lingual, thyroid, and submaxil- 

 lary veins, ib. g, h, i. 



* The jugular veins form a remarkable communication with 

 each other immediately below the cranium, by means of a cross 

 branch, generally of an equal size Avith the trunks themselves. 

 From each side of the arch thus formed there issues a large 

 vessel, which is made up of the veins of the external part of the 

 head; one of these passes round the tympanic, and apparently 

 penetrates the joint of that bone with the lower jaw ; it appears 

 in several branches upon the side of the cheek, and contributes 

 to form a plexus of veins below the posterior part of the orbit, 

 ib. k, similar to the arterial plexus already described in that 

 situation. The principal branch of the veins of the head passes 

 obliquely round the pterygoid bone, and below the orbit di\ddes 

 into several large vessels, one of which belongs to the back part 

 of the palate ; another ascends on the orbit, and unites with the 

 ophthalmic vein ; and a third is distributed to the interior of the 

 organ of smell, the palate, and the external parts of the upper 

 and lower jaws. These branches produce plexuses along the 

 l)ase of the orbit and the external edge of the palate, which 

 correspond to those of the arteries before described.' ^ 



The sinuses of the brain are irregular in form, and consist of 

 flattened canals. The principal ones, besides those upon the 

 cerebellum, are the superior longitudinal, and one which runs 

 along the lower edge of each hemisphere of the cerebrum ; there 

 appears to be also one upon the side of the cerebellum, corre- 

 sponding to the lateral sinus. All these sinuses communicate 

 with each other on the back of the cerebellum, and seem to dis- 

 charge their contents principally into some veins which lie in the 



