98 Journal of Comparative Neurology. 



lines were traced also with the camera. Liability to distortion due to the en- 

 largement of the parts of an uneven surface was materially reduced. Figures 

 I, 2, 3, 4, 5, 6. 7, 21, 25, 31, were photographed natural size and enlarged from 

 ■photographs or figures as indicated, with an enlarging apparatus. Figures S, 

 17, 18, 19, 20 and 34 were photographed as stated and traced from photographs. 

 Fig. 12 was made from outlines traced from photographs of lateral views 

 before and after dissection. 



abbreviations. 



art. — artery. /. "/. — postoperculum. 



circ.f. — circuminsular fissure. prein. — preinsula. 



cl. — claustrum. Preop. — preoperculum. 

 Ji. olf. tr. — myelinic fibres of olfactory rh. f. — rhinal fissure. 



tract. stibop. — suboperculum. 



j«.— insula. .Sj'. /.—Sylvian fissure. 



op. — operculum. tr.f. — transinsular fissure. 



P. — Pole of the Insula. z. f. — zygal fissure. 



/()j//«.— postinsula. v. f. — vertical fissure. 



DESCRIPTION OF FIGURES. 



The numbers are the serial numbers of the Museum of Vertebrate Zoology 

 of Cornell University. 



PLATE IX. 



Fig. J. Lateral aspect of the left half of the brain of a human fetus, size 

 and age unknown. 2278; x i (after Wilder, 63, Fig, 4760). 



Fig. 2. Ventral aspect of the left cerebrum of a human foetus, size and 

 age unknown. 1820; x i (after Wilder, 64, Fig. 4782). 



Fig. 3. Lateral aspect of right human insula, age and sex unknown, adult, 

 1805; X I. The insula was exposed by cutting away the surrounding lobes 

 down to the level of the circuminsular fissure, thus exposing the medicornu and 

 hippocamp. The three eminences i, 2 and 3 belong to the postinsula. The 

 fissure marked 4 is too sharply outlined near the ventral end. At the point in- 

 dicated it is a mere vasal furrow and does not communicate with the Sylvian 

 fissure ventrad. 



Fig. 4. Lateral aspect of right human insula, age and sex unknown, 

 young, 1823; X I. This preparation shows the branches of the raedicerebral ar- 

 tery as it divides over the surface of the insula. The largest branch lies in the 

 transinsular fissure for about two thirds of the distance across the insula, then 

 leaves this fissure and bends caudo-dorsad as if towards the Sylvian. There is 

 also shown a tendency toward the demarcation of an eminence similar to that 

 shown in Fig. 3. 



Fig. J. Uorso-lateral aspect of the right human insula, age 37 years, 

 male, 376 ; x i. A nearly normal insula except for the unusually e^evated pole, 

 F. The short furrow cephalad is represented too deep and too narrow. 



Fig. 6. Caudal aspect of a transection of the left cerebrum of man, after 

 Wilder (6-i, 4732). Shows the relation of the insula to the claustrum, the brain 

 stem and operculums. 



