May 2G, 1905.] 



SCIENCE. 



813 



particularly large examples may have given 

 color to the belief in the 'sea-serpent.' 

 Garman's example was ill-preserved and 

 the brain obviously in poor condition; 

 the Cornell specimen is quite perfect. 

 Scymnus has been long known; it is a 

 rather ordinary-looking shark and occurs 

 also in the Mediterranean, but it seems not 

 to be very common, at any rate Professor 

 Wilder has been unable to obtain a well- 

 preserved specimen, and only recently has 

 obtained a brain through the generosity of 

 Professor Locy, of the Northwestern Uni- 

 versity. 



Professor AA''ilder's special reason for 

 studying the brain of Scytnnus has been 

 his wish to confirm or correct the account 

 given in 1882 by the late T. Jeffery Parker, 

 of New Zealand. According to this 

 writer Scymnus * exemplifies with diagram- 

 matic clearness the typical structure of the 

 vertebrate brain.' Professor Wilder finds 

 that it really resembles more nearly the 

 brain of Heptanchus and the earlier fig- 

 ures of Busch and Maclay; and this was 

 to be expected since Scymnus is not, as to 

 its other structures and its extinct relatives, 

 such a very primitive type. But the 

 simple conditions ascribed by Parker to 

 Scymnus are more closely embodied in the 

 anguin or frilled shark, whose cladodont 

 relatives were in the Devonian epoch and 

 which Garman regards 'the oldest [known] 

 living type of vertebrate.' Here the walls 

 of the forebrain are thinner and less dif- 

 ferentiated, and in the lateral extensions 

 toward the olfactory cups ('nostrils') the 

 so-called cerebral portion expands nearly 

 equally in every direction from the axis 

 represented by the olfactory eruss ; in most 

 other sharks and in rays or skates the 

 special cerebral extension is toward the 

 meson or middle line, so as to meet the 

 corresponding part of the other side; in 

 the lamprey the cerebral extensions are 



away from the meson ; in the Dipnoi, as 

 shown by the speaker in 1887, they are 

 downward, while in the ordinary and 

 higher air-breathing vertebrates, reptiles, 

 birds and mammals, the cerebral hemi- 

 spheres expand mostly upward. It is as if 

 nature had experimented in the four direc- 

 tions at right angles with one another from 

 the primitive condition, nearly as in 

 Chlamydoselachus, where the extension is 

 almost uniformly in all directions from the 

 olfactory axis. There were shown dia- 

 grams illustrating this idea, and also the 

 possible derivation of the several grades 

 of shark and ray brains from the hypothetic 

 stem form, probably extinct and now in- 

 ferred only from the embryonic conditions 

 of recent forms. In this connection the 

 speaker reiterated his previously expressed 

 conviction that in evolution the olfactory 

 portion of the brain had preceded the cere- 

 bral; that the ancestral vertebrates needed 

 to smell rather than to think; that the 

 organ of forethought had been, so to speak, 

 an afterthought, and that the cerebral re- 

 gion, so preponderant in man, was rather 

 an offshoot from the olfactory region, and 

 had been interpolated between that and the 

 hinder portions of the brain. The primi- 

 tive preeminence of olfaction he regards as 

 supported by the recent observations of 

 Locy and others upon a nerve in most 

 (probably all) sharks and rays and in 

 some other generalized forms, connecting 

 the nasal mucosa with the very front of the 

 brain, and so slender as to have been com- 

 monly overlooked; in Mitsukurin-a, where 

 the olfactory crura are extremely long, 

 the nerve has been most skillfully worked 

 out by Locy, to whom the Cornell brain was 

 sent for the purpose. Although, from its 

 late discovery, sometimes called the 'new 

 nerve,' Professor Wilder thinks, perhaps, 

 it is the very oldest ; as suggested by Locy, 

 its functions have been replaced by others, 



