ELASMOBRANCH BRAIN ORGANIZATION 



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2 mm 



Figure 6 Photomicrographs of comparable transverse sections through rostral, mid, and 

 caudal levels of the right telencephalic hemishpere of (A.C.E) the spiny dogfish, Squalus 

 acanthias, and (B.D.F) the smooth dogfish, Mustelus canis, illustrating the reduction in 

 lateral ventricles and marked hypertrophy of the roof (pallial) neural groups that occur in 

 carcharhiniform sharks, as, area superficialis basalis; en, central nucleus; dp, dorsal pal- 

 lium; fb, forebrain bundles; Is, lateral septum; lp, lateral pallium; mp, medial pallium; ms, 

 medial septum; ob, olfactory bulb; pa, preoptic area of hypothalamus; st, striatum. 



