150 |oiM{NAL OF CoMl'AKATlXK N EJ^' U()I.()(;Y. 



both are referred to as seems most convenient. No attempt 

 is made to give reference to the extensive literature of this 

 subject, though a partial list of papers is appended. 



The brain of the Gar-pike [Lcpidosteus) may serve as 

 a convenient standard of reference for fish brains. If it could 

 have been satisfactorily studied before that of the aberrant 

 Teleosts, science would have been saved a long period of 

 grouping and a vast deal of confusing synonomy. 



The olfactory lobes are generally unmistakable, but 

 where, as in the cods, separated by a wide interval from the 

 hemispheres they have been overlooked, leading to an identi- 

 fication of the cephalad part of the hemispheres with the 

 olfactories. The microscopic structure of the olfactory lobes 

 is so unmistakable that there is no excuse for the confusion. 

 The second paired or apparently fused bodies have been very 

 diff'erently interpreted. Haller supposed them organs of 

 smell, together with the hypoaria. Kuhl, Gottsche, Mayer 

 and others homologized them unhesitatingly with the olfac- 

 tory lobes. Philipeaux and Vulpian thought they represent 

 the caruncula mammillaris of the olfactory. Tiedemann 

 thought he discovered in them the homologues of the striata 

 and herhispheres. Though most of the later writers have 

 accepted some phase of this interpretation, the apparent 

 absence of the lateral ventricles or the attempt to homologize 

 the olfactory ventricle with them has led to great diversity 

 in minor points. The third pair of dorsal tuberosities is often 

 apparently single, and, though it has often been identified 

 with the optic lobes, yet, because of a failure to recognize 

 the thalamus (which scarcely reaches the dorsal surface in 

 many fishes), it has been given every possible name. Very 

 generally, among the earlier writers, it has been called the 

 cerebrum, and the Sylvian commissure poses as corpus 

 callosum. Two projections into the ventricles of the optic 

 lobes have been identified as the fornix (Gottsche). Cams 

 and Tiedemann, the one from comparative, the other from 

 eiiibryological considerations, identified these bodies with 



