284 



shown in Koelltker, Handbuch der Gewebelehre des Menschen, Bd. 2, 

 1896, for he pictures sections of about the same stage as the model 

 cut perpendicularly to the long axis. 



The first section represents the spinal cord above the cervical 

 swelling. The second passes through the decussatio lemniscorum 

 and is a little farther cerebralward than Koelliker's Fig. 443. The 

 third is a typical section of the medulla and corresponds with Fig. 466 

 except that the nucleus funiculi cuneati occupies the place of the radix 

 descendens n. vestibuli. The fourth passes through the nucleus of the 

 N. abducens and corresponds with Fig. 490, while the fifth passes 

 through the upper part of the pons just spinalward from the N. 

 trochlearis. It is to be compared with Fig. 559. The sixth section 

 passes through the midbrain at the level of the superior colliculus as 

 shown in Fig. 567. Koelliker has two more figures, namely 560 and 

 561, which pass through the inferior colliculus and show, as does the 

 model, that at birth the inferior colliculus lies opposite the peduncle 

 rather than opposite the pons as in the adult. That is to say, the 

 growth of the pons is forward or cerebralward. 



The second model shows the surface form on the right side, and 

 the structures just beneath the surface on the left (Fig. 1). The 

 transverse lines represent the position of the sections of model I. 

 The lower end of the model is the same as the first section of 

 model I, and represents the spinal cord. The relations of the dorsal 

 funiculi to their nuclei as well as the origin of the corpus restiforme 

 from the dorsal funiculi and the fasciculus cerebrellospinalis are clearly 

 shown. 



This model also shows the relation of the three cerebellar peduncles 

 to each other. The middle peduncle, or brachium pontis is non- 

 medullated and shows as a narrow band on the surface form on the 

 right hand side. The superior and inferior peduncles have been pro- 

 longed slighthy free hand by the aid of transverse sections in order 

 to show their relative positions as they enter the cerebellum. The 

 superior peduncle or brachium conjunctivum passes obliquely dorsal- 

 ward to the corpus dentatum, the anterior, ventral tip of which is 

 shown in outline. — The inferior peduncle or corpus restiforme passes 

 dorsalward just lateral to the anterior tip of the corpus dentatum and 

 to the brachium conjunctivum. 



Certain of the relations in the midbrain are also clearer in this 

 model than in any other. For example the position of the lemniscus 

 medialis with regard to the pyramidal tract, the red nucleus and the 

 substantia nigra. 



