STNONTMS AND REFEREyCES. 475 



Next to the cerebrum, the largest portion of the brain. A single foliated mass, form- 

 ing with the valvula the dorsal part of the epencephalon and constituting the roof of part 

 of the epicoelia. 



§ 1201. Cerebrum (az.), cJ.— Fig. 88, 104, 118-117, 124, 125 ; PI. I, Fig. 1, 3 ; PI. II, 

 Fig. 3, 4 ; PI. Ill, Fig. 5. 6, 13 ; PI. IV, Fig. 14^20. Gray, A, 615 ; Quain, A, II, 522. 



8yn. — ProsenoephaloD, hemisphserae. 



The largest portion of the brain, forming two convoluted lobes between the Lobi olfae- 

 torii and the tlialami ; the former are partly, the latter wholly, covered by them. The 

 striata and hypocampm are thickenings of certain parts. 



The thalami and optiei are not properly " internal parts of the cerebrum." 



§ 1202. Chiasma {az.), eh.—Fig. 116-118 ; PI. II, Fig. 3, 4; PI. Ill, Fig. 5, 11 ; PI. IV, 

 Fig. 16. Gray, A, 631, 639; Quain, A, II, 536. 



8yn. — Chiasma nervorum opticorum, optic commissure. 



The subcylindrical x-shaped mass at the base of the brain formed by the union and 

 decussation of tlie two optic tracts ; from it the NN. optiei pass to the eyes. 



Remark — We are not aware that special observations have determined the extent of 

 the crossing or decussation of the fibers at the chiasma in the cat ; the precise arrange- 

 ment seems not to have been determined for man (Meynert [Strieker, A, 688] ; Ferrier, 

 A, -72 ; Wadsworth, 1, 528). 



§ 1303. Cimbia, cmh.—Fig. 116, 118 ; PI. II, Fig. 3 ; PL III, Fig. 9, 11 ; § 1142. 



8yn. — Tractus transversus pedunculi — Gudden, as quoted by Meynert (Strieker, A, 737). 



A fibrous band crossing the Crus cerebri just cephalad of the octal origin of the N. ocu- 

 Inmotorius. It may be traced from between the opticus and the postgeniculatum to near 

 the ventrimeson, where it suddenly enters the crus. 



The senior author has suggested (14:, 554) that the cimbia may be regarded as indicat- 

 ing the line of junction between the mesencephalic and diencephalic portions of the criu. 

 The name was proposed as a brief substitute for Gudden's descriptive term ; it signifies in 

 architecture a band or fillet about a column. 



§ 1204. Cinerea, (Substantia), cin.-V\. Ill, Fig. 13; PI. IV, Fig. 14,15,20; §995. 

 Gray, A, 622 ; Quain, A, II, 558 ; Meynert (Strieker, A, 651). 



8yn. — Gray matter, ganglionic or cellular nervous tissue, vesicular neurine. 



The myelonal cinerea has been mentioned in § 998. The encephalic cinerea is arranged 

 by Meynert (Strieker, A, 651) in four categories : cortex cerebri; basal ganglia [striata and 

 thalami] ; central tubular gray [lining the cceliae] ; cerebellar cinerea. The central tubular 

 gray is the subject of a paper by Spitzka (]). 



% 1305. Clava, dv.—Fl III, Fig. 13. Gray, A, 612 ; Quain, A, II, 505. 



Syn. — Processus clavatus, funiculus gracilis, pyramis posterior. 



The slender fibrous band forming the margin of the metacoelia. It Is the cephalic con- 

 tinuation of the slender " posterior median column " of the myelon. 



The name is used in accordance with the remark of Spitzka (7, 165). We have not 

 encountered it elsewhere. 



§ 1306. Columna dorsalis (myelonis), am. d.—Fig. 113 ; PI. I, Fig. 1 ; PI. II, Fig. 13. 

 Gray, A, 605 ; Quain, A, II, 494. 



Syn. — Columna posterior, the " posterior white column of the cord." 



Excepting iu Fig. 113, no distinction is indicated between the larger Clm. dorsalis and 

 the smaller and more mesal "posterior median column," which is commonly regarded as 

 merely a part thereof, and is continued as the clava. 



S 1307. Columna fomicis, am. /.—Fig 113, 117, 133 ; PI. II, Fig. 4 ; PI. Ill, Fig. 

 13 ; PI. IV, Pig. 14, 16. 30 ; § 1145. Gray, A, 638 ; Quain, A, II, 543. 



