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IIoLT, E. W. L. Observations upon the Development of the Tele- 

 ostean Brain, with Especial Reference to that of Clupea harengus. 

 Zool. yahrhucli., Morph. Abth.. Bd. IV. 



The first paper, that of Prof. Wilder, relates to the 

 present group. We quote as follows: "The front pair of 

 lobes [of the the fish brain] have usually, not always, been 

 called olfactory lobes. In Myzonts or Marsipobranchs (lam- 

 prey eels, etc.), in Ganoids and some Teleosts, as in higher 

 vertebrates they are sessile; but in many Teleosts and most, 

 if not all, Selachians (sharks and skates) they are connected 

 by elongate crura with the second lobes. These latter are 

 almost viniversally called hemispheres. Yet the essential 

 feautures of hemispheres, namely, lateral ventricles and 

 foramina of Monro, have never been found in the second pair 

 of lobes of any fish-like form excepting those of the Dipnoans 

 [Lepidosireji, Protoptcrus^ and Ccratodus) , which seem in 

 most respects more like those of Batrachians than of fishes. 

 The second pair of lobes are either solid lateral laminae joined 

 below, but with the upper borders more or less everted, as 

 in Teleosts and Ganoids, or joined above also so as to inclose 

 a cavity, as in Salachians. In either case the median space 

 must be regarded as a forward continuation of the median or 

 third ventricle, and the lateral walls as enlargements of the 

 thalami. These enlargements Prof Wilder proposes to call 

 protlialatni ; in vSalachians and Ganoids they are connected 

 by more or less elongated and depressed crura thalavii with 

 the optic lobes behind. From the anterior part of the space 

 between the prothalami and, in Ganoids and Teleosts, appar- 

 ently in the base of the olfactory lobes, are two openings 

 leading into the cavity of the olfactory lobes. These open- 

 ings are regarded as foramina of Monro, leading into dis- 

 tinct, though small, lateral ventricles." "The true hemi- 

 spheres of (ianoids may be represented by a raised lip of the 

 foramen of Monro." 



We think the failure to recognize the well-defined hemi- 

 spheres in this case was due to the peculiar membranous 



