62 PHYSIOLOGICAL SERIES. 



texture is ligamento-cartilaginous. This moveable cartilage is 

 connected with both the condyle of the jaw and the articulating 

 surface of the temporal bone, by distinct ligaments, arising from 

 its edges all round. That by which it is attached to the temporal 

 bone is the most free and loose ; though both ligaments will allow 

 an easy motion, or sliding of the cartilage on the respective sur- 

 faces of the condyle and temporal bone. These attachments of 

 the cartilage are strengthened, and the whole articulation secured, 

 by an external ligament which is common to both, and which is 

 fixed to the temporal bone and to the neck of the condyle. On 

 the inner surface of the ligament which attaches the cartilage to 

 the temporal bone, and backwards, in the cavity, is placed what is 

 commonly called the gland of the joint ; at least, the ligament is 

 there much more vascular than at any other part." Hunter, On 

 the Teeth, 4to, 1st edit., 1771, p. 9. 



Hunterian. 



VBKTEBEAL COLUMN. 



ACENTROUS. 



Gadow & Abbott, Phil. Trans., vol. clxxxvi. 1895, p. 163, 

 & Gadow, vol. clxxxvii. 1896, p. 1. 



B. 68. Three portions of the notochord of a Sea-Lamprey 

 (Petromyzon marinus), showing a series of cartilaginous 

 dorsal arches lying in the lateral walls of the mass of con- 

 nective tissue that surrounds the neural canal. 



In the anterior region of the body (middle specimen) 

 the arches are irregular in shape, but further back, in the 

 region of the liver (lower specimen), they are more 

 regular. 



The upper specimen is a transverse section through the 

 anterior region and shows the relation of the arches to the 

 neural canal. 



Schneider, ' Beitrage zur vergleichenden Anatomie und 

 Entwicklungsgeschichte der Wirbelthiere,' Berlin, 

 1879, p. 51. 



B. 69. Portion of vertebral column, and head of a Sea-Lamprey 

 (Petromyzon marinus). The ventral portion of the noto- 

 chord and cartilaginous cranium has been removed in front 



