Method XX 123 



lingula, lobus centralis, and monticulus ; the vermis infierior, with 

 its nodulus, uvula, pyramis, and tuber vermis. In the mesial 

 aspect (cut surface) of the hemisphere show further the arbor 

 vitae, consisting of corpus medullare, laminae meduUares, and 

 substantia corticalis (cerebellar cortex). Identify the flocculus. 

 What is the nature of the velum medullare anterius and its 

 relation to the brachium conjunctivum ? 



4. Isthmus rhombencephali, showing velum medullare anterius, 

 brachium conjunctivum, anterior portion of ventriculus quartus 

 leading into the aqueductus cerebri (aqueduct of Sylvius), and fila 

 lateralia pontis. 



5. The mesencephalon, showing the N. trochlearis and corpora 

 quadrigemina consisting of colliculi inferiores (testes) and colli- 

 culi superiores (nates); the brachium quadrigeminum superius 

 and inferius, and corpus pineale. 



Include also corpora geniculata mediale and laterale, and 

 pedunculus cerebri. The corpora geniculata and corpus pineale 

 belong to the thalamencephalon. A part of the overhanging 

 occipital lobe and a part of the thalamus opticus should be 

 included to show the relation of the mesencephalon to the parts 

 anterior to it. 



What structures are to be observed on the ventral surface of 

 the mesencephalon ? Identify the trigonum habenulae. 



(c) Prosencephalon. — i. Fades medialis: Sever the remaining 

 pedunculus cerebri, taking care not to injure the mesencephalon 

 and thalamencephalon. Return the rhombencephalon and mesen- 

 cephalon thus detached to the formalin solution. Make a draw- 

 ing of the entire mesial surface of the prosencephalon now 

 exposed, illustrating the shape and position of the following 

 structures : 



Commissura anterior, and corpus callosum consisting of sple- 

 nium, truncus, genu, and rostrum corporis callosi. 



Septum pellucidum, lamina rostralis, and lamina terminalis. 



Tela choroidea ventriculi tertii, thalamus opticus, massa inter- 

 media (middle or soft commissure), and chiasma opticum. 



Remove a portion of the septum pellucidum to show a part 



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