Clark, Comparative Anatomy of the Insula. yy 



but they were not available for examination at the time this 

 thesis was prepared. 



In 1866, Flower (21) said of the Javan loris {Stenops 

 Javanicus) on separating the lips of the Sylvian fissure " no 

 distinct median lobe, or insula, could be traced." The same 

 author also says " In the sulci of the outer face in the lemur, 

 the Sylvian fissure is deeper especially at its anterior or lower 

 part and conceals a small but distinctly marked insula or me- 

 dian lobe." 



ORDERS CHEIROPTERA AND INSECTIVORA. 



The specimens belonging to the above named orders, so far 

 examined by the writer, showed no evidence of a macroscopic 

 insula. 



THE INSULA IN THE CARNIVORA. 



The area which represents the insula in this order is, in 

 general, not well developed, but in a more or less rudimentary 

 form may be said to be fairly constant. As a macroscopic area, 

 however, I have been unable to recognize it in the domestic cat, 

 the Angora cat, Ly)ix ricfus, the ocelot {Felts pardalis), the 

 skunk {Mephitis inephitica), the mink {Pntorins visofi) and the 

 ferret {Putorius domcsticd). My observations made in the 

 latter part of 1893 upon the seal {Phoca vitulina) agree with 

 the conclusion of .P. A. Fish (20 K. 16, 1896) who has 

 shown that the Sylvian fissure has not suffered any 

 marked displacement and that Spitzka (1890, American Nat- 

 uralist, XXVI, 1 15-122) erred in assuming a vertical com- 

 municating fissure (7'. f. Fig. 9) as the true Sylvian. The posi- 

 tion of the insula shows conclusively that the caudal one of 

 these two fissures is the true Sylvian. Dr. Fish also says: "The 

 vertical and the true Sylvian fissures meet superficially at the 

 latero-ventral angle of the cerebrum and if the sides of the Syl- 

 vian be separated, it will be seen that the vertical fissure in- 

 stead of directly joining the Sylvian becomes a submerged fis- 

 sure . . . and crops out again on the ventral surface on 

 the front or cephalic wall of the mouth of the Sylvian. 

 This condition is found on both sides." The insula is repre- 



