82 



LECTURES 



New Zealand, known to the zoologist as Hatteria, discov- 

 ered that it possessed on the vertex of its skull, in the 

 mid-parietal region, a small perforation or foramen, and 

 in the brain beneath it, in the median plane, the more 

 than evident rudiments of an eye a third, mid-brain 

 eye. This structure was connected with the brain below 

 by its nervous stalk, the proximal extremity of which, or 

 its root, corresponding to the origin of the glandular 

 structure just spoken of as the pineal gland, which occurs 

 in so many other animals. Morphologists immediately 

 examined a great variety of other lizards in various parts 

 of the world, and many were found to possess it in differ- 

 ent states of perfectness. Tracing it through the animal 

 series, it soon became evident that in its nearly com- 

 pletelv rudimentary condition in man and the higher 

 mammalia it is now but represented in them by the 

 pineal gland, or the basal, vestigal end of the nervous 

 root-stalk. 



Another very interesting example of this sort is the 

 discovery, a few years ago, by my talented friend, Dr. J. 

 Bland Button, the British anatomist, of the morphologi- 

 cal import of the round ligament of the hipjoint. This 

 structure has long been an anatomical puzzle, and is 

 technically known to aratomists as the ligamentum teres. 

 In man it is a round ligamentous cord passing from a 

 shallow pit on the head of the thighbone to the base of 

 the articulaiory socket for that bone situated at the 

 side of the pelvis. All sorts of opinions have been held 

 concerning its nature, but the researches of Dr. Sution 

 have, it would appear, settled the question; and he has 

 quite conclusively shown that the ligamentum teres must, 

 originally have formed a part of the pectineus muscle, 

 one of the muscles of the upper part of the thigh and 

 hip. The ligament is very generally found in the mam- 

 malia, though that class offers a number of remarkable 

 exceptions. So far as at present known but one bird lacks 

 it, and that is the cassowary (Casuarius appendiculata), 

 while in reptiles it has thus far been found to be univer- 

 sally present, being represented by a ligamentous band. 



"It is in the horse that we first get the glimpse of the 

 true nature of the ligament, for in this animal it consists 

 of two parts, one hidden within the joint termed the coty- 

 loid portion, the other passes out of the cavity to join the 

 linea alba at its jumction with the pubes, hence it is 

 termed the pubio-femoral portion. From this band the 

 pectineus takes origin. * ' 



"In the ostrich the ligamentum teres has a true tendinous 



