82 Journal of Comparative Neurology. 



The significance of the presence of the claustrum is diffi- 

 cult to determine. As previously stated, the existence of a 

 claustrum might, in general, be taken to indicate the presence 

 of an insula but such is not believed to be true in either of 

 these instances. Presumably if a rudimentary insula did exist in 

 the cat, then only a small portion of the claustrum would corres- 

 pond therewith ; and if only a part of the claustrum belongs to 

 this area, then, as in this case where the claustrum is of consid- 

 erable size, the larger part of the claustrum has necessarily no 

 conection with the insula. Indeed it might exist quite as well 

 without an insula. Hence it would appear that the only signifi- 

 cance attached to the presence of a claustrum in such cases is 

 that the cortex at the bottom of the Sylvian fissure is relatively 

 farther entad than in those brains where the area is not so de- 

 marcated, as in the sheep and mink. 



Turner in 1888 (59^ 566) said: "In the true carnivora, the 

 Sylvian convolution was, as a rule, superficial and on the cra- 

 nial aspect, though in the otter and badger indications- of the 

 depression of its anterior limb within the fissure were seen. In 

 the seals and walrus, the concealment of this convolution was 

 still more marked, so that the brains of these animals form ap- 

 parently, in this particular, a transition to those of man and apes, 

 in which the concealment of the island is complete." 



THE INSULA IN THE PROBOSCIDIA. 



In the single specimen of the Indian elephant exarnined 

 by the writer, the insula (Fig. 21) is only slightly developed. 

 It consists of an almost flat area in the bottom of the Sylvian 

 fissure and is made up of three gyres, two of which belong 

 to the postinsula. This disposition of the insular area suggests 

 that in the unusual dog (Fig. 16) except that in the latter the 

 postinsula is at the same time more elevated. In the elephant 

 the postinsula contains the greater number of gyres but the 

 preinsula is the more elevated. The entire area is deeply 

 imbedded in the Sylvian fissure and extends ventrad as far as 

 the rhinal fissure. This observation is contrary to that of Owen, 

 1868, who declares (44, 129) that "the minor inter-Sylvian con- 



