ELASMOBRANCH BRAIN ORGANIZATION 



135 



2 mm 



Figure 10 Transverse sections through the right telencephalic hemisphere of an hex- 

 anchiform shark, Notorynchus maculatus. The levels of these sections are indicated in 

 Figure 9. a, cell group a (possible pallial amygdala); as, area superficialis basalis;cn, central 

 nucleus; dp, dorsal pallium; fb, forebrain bundles; Is, lateral septal nucleus; lp, lateral 

 pallium; mp, medial pallium; ms, medial septal nucleus; pa, preoptic area; st, striatum. 



important being that it is a numerical quantity whose biological significance 

 is unknown. Fortunately, Jerison (1970, 1973) has critically reviewed the 

 problem of brain: body indices and has suggested that the philosophy of 

 curve fitting based on the assumption that samples represent random 

 deviations of a true mean (caused by measurement error) should be replaced 

 by a curve-fitting procedure that assumes that the samples represent a region 



