334 N. AV. INGALLS 



surface markings of the brain, but with a constantly diminishing 

 probability of error as our knowledge increases. Only after an ex- 

 haustive examination of the entire cortex could one begin to 

 speak dogmatically and then only of the particular brain investi- 

 gated. Such an herculean task is quite out of the question for any 

 large series of brains and for the vast majority of those which 

 come into our hands we must be content with an approximation of 

 the true conditions. 



We shall not take time here to discuss a number of separate 

 cases but shall endeavor to apply the reasoning contained in 

 the foregoing pages. Primitive types of configuration are natur- 

 ally desirable and instructive, where one can sometimes find a 

 strikingly pithecoid pattern, and it is to one of these that we shall 

 call attention. 



Figures 18 and 19 represent the posterior portions of the right 

 and left hemisphere of a Soudanese negress. The pattern is 

 simple and clear, almost diagrammatic, all the typical fissures 

 being present with very few others. Other primitive brains which 

 have been recorded, Tasmanian, Australian, Egyptian, etc. 

 would have served our purpose also. We shall base our discussion 

 upon this brain, referring to the varying conditions found else- 

 where. 



The lunate sulcus is as typical as could be desired, especially on 

 the right side. It is deeply operculated and in every way indi- 

 cative of an unusually extensive area striata. Lunate sulci are 

 not, as Cunningham supposed, unusual, a search through any 

 work where a considerable series of brains is figured will reveal 

 numbers of cases. Many can be found in the Swedish brains of 

 Retzius ('96), more recently Murphy has published some very 

 well marked examples, especially in the negro, and Elliot Smith 

 has shown them in Tasmanian and Australian ('11) and in numer- 

 ous Egyptian brains ('04). Although doubtless of little value as a 

 racial characteristic, they are, when very well developed, sugges- 

 tive of less advanced conditions in the surrounding areas which 

 have allowed a typical lunate to be formed. One might confi- 

 dently expect to find cases in any large series of brains from any 

 source. 



