382 PROF. G. ELLIOT SMITH OX THE 



liowever, found it in the Apes and Seals [cliez les Singes et les Plioques] " *, gained a 

 wide currency in the text-Looks of the period t, and have even persisted in certain French 

 treatises np to tlie present day. And yet this important fact has been wholly ignored 

 in the discussion of the possible homologues of the calcarine sulcus in other mammals. 



[In making this statement I am not unmindful of the fact that in the memoirs of 

 Murie on the brain in the Seals and in the Manatee an anthropocentric nomenclature is 

 adopted and a furrow on the surface of the hemisphere is called " calcarine " ; Murie 

 also describes a posterior cornu and a calcar in Otaria and Manatus7\ 



The calcar was rediscovered and described in the brain of the Seals by Fish in 1898 ; 

 but this writer so signally failed to appreciate the morphology of this region of the brain 

 as to entertain a doubt as to wlietlier the sulcus, which produced this calcar, ought to 

 l)e regarded as the calcarine or the parieto-occipital ! %. He makes the following 

 quotation from Wilder's " Anatomical Technology " : — " Between the ordinary Carnivora 

 and the Monkeys are two groups whose brains should be studied with especial care ; 

 the Seals liave a rudimentary postcornu and occipital lobe, and these parts are said 

 to be developed in the Lemurs which have aflQnities with both the Carnivora and the 

 Primates " (p. 80). 



Although Fish quotes the statements of Tiedemann, who represents Fhoca as lacking 

 a posterior cornu, he appears to be ignorant of the above-quoted observation of Serres, 

 in spite of its Avide cui'rency in such works as those of Cuvier, Leuret and Gratiolet, and 

 Topinard. His suggestion that the splenial sulcus of the Piunipedia may possibly 

 represent the parieto-occipital sulcus becomes all the more amazing when he makes such 

 definite statements as: — " [^Phoca'] shows a jjostcornu relatively as large or larger than 

 in the primate brain, with a distinct calcar or hippocampus minor in which a portion of 

 the splenial appears as a total fissure " (p. 88). 



I have confirmed all these statements of fact in the Seals and prepared a dissection 

 of this region in Phoca for the Musevim of the Eoyal College of Svu'geons (Si^ecimen 

 D. 377, Physiological Series). 



Since Krueg carefully described and named the " splenial " sulcus in a large number 

 of Carnivores and Ungulates, no one has questioned the identity of the furrows so-named 

 in the two Orders. The different position of the furrow on the hemisphere in the 

 Ungulata modifies its obliquity so that it does not so closely resemble the calcarine 

 sulcus in the Primates as that of the Carnivora does. Xevertheless the relationship of 

 its two walls to the lateral ventricle and its depth (in comparison with neighbouring 

 sulci) would suflBice to show its identity, even if we w^ere not acquainted with its 



* ' Anatomic Coiuparee du Cerveau,' Paris, 1826, t. ii. p. 470. 



t Vide Leuret, " Aiiat. Comparec du Systeme Nerv." tomo i. 1839, p. 402, and a fuller account in Gratiolet "s 

 edition of the same work, tomo ii. 18.57, p. 74. 



t P. A. Fish, " The Praia in the Fur-Seal, Callorhinus iirsiniis ; with a Comparative Description of those of 

 Zaiophus, Phoca, Ursas, and MonacJius," Journal of Comparative Neurology, vol. viii. nos. 1 and 2, July 189S, p. 79. 



" The conditions .... might naturally suggest homology with the ape and human calcar and that the splenial 

 fissure, in this seal possessing a postcornu, might he homologized with the occipital [the contest shows that this 

 term undouhtedly refers to Uio parieto-occipital sulcus] or calcarine fissure in Man," 



