January 8, 189?.] 



SCIENCE. 



17 



lowest avian brains, with their large projecting olfactory lobes 

 and uncovered optic lobes, and the highest avian brains, with 

 their small, inconspicuous olfactory lobes and covered optic 

 lobes. The diEFerence between these two extremes is almost 

 as great as that between the brain of a lizard and the brain 

 of the lowest type of birds. Yet there is no impassable gulf 

 between these two extremes. All the intervening stages are 

 supplied by the brains of the various avian groups. In re- 

 viewing this remarkable sequence, we are almost forced to 

 believe that this tendency towards a progressive compactness 

 of the brain existed long before the first bird was evolved. 

 If this be true, then this tendency towards a progressive com- 

 pactness of the brain, combined with a tendency to develop 

 all parts appertaining to vision and to atrophy all parts ap- 

 pertaining to smell, will account for all the major differences 

 between the avian and the reptilian brain. 



Furthermore, within this class of animals, this "progres- 

 sive compactness " of the brain is a factor of taxonomic im- 

 portance. So far at least as major groups are concerned, a 

 classification based upon it alone is, for the most part, in 

 harmony with those classi6cations that are based upon other 

 structural elements of birds. 



Histologically considered, the bird brain is composed of 

 nerve fibres, nerve cells, and neuroglia. Excepting the for- 

 nix and hippocampal commissures, all the principal com- 

 missures of the mammalian brain, corpus callosum included, 

 are found in the avian brain. Poverty of space causes the 

 omission, in this abstract, of the various other tracts of the 

 bird brain. 



Although in the bird brain the nerve cells present a great 

 diversity of forms, yet they may all be grouped in the fol- 

 lowing classes: ganglionic cells, Deiter's corpuscles, fusiform 

 or flask cells, pyramidal cells, and multipolar cells. The 

 ganglionic cells are large bi-polar cells, which are never found 

 outside of the root ganglia. Each extremity of the cell is 

 prolonged into a nerve fibre. One fibre passes into the brain, 

 the other into a nerve. In addition to the ordinary cell wall, 

 each of these ganglionic cells is surrounded by a special 

 nuclei-bearing sheath. Deiter's corpuscles are small cells, 

 which are supplied with so small an amount of protoplasm 

 that ordinary preparation reveals nothing but their nuclei. 

 These minute cells are universally distributed. In the cere- 

 bellum, however, they are densely aggregated in a single 

 lamina; while in the optic lobes they are densely aggregated 

 in several concentric laminse. The remaining three types 

 are encountered throughout the brain; but in any single 

 nidulus some type always predominates, often to the exclu- 

 sion of the other two. The flask cells resemble a flask in 

 shape, and when stained each cell presents a faintly stained 

 nucleus, within which is a densely stained nucleolus. Such 

 cells are supposed to function as sensory cells. The pyra- 

 midal cells are sub-pyramidal in outline. These cells stain 

 densely, when each one presents a densely stained nucleus, 

 within which is a densely stained nucleolus. Such cells are 

 probably motor in function. The multipolar cells resemble 

 distorted, many-branched, pyramidal cells. Such cells proba- 

 bly act as switch stations for nervous energy. 



University of Cincinnati, Dec. 31, 189'. C. H. TURNER. 



The remains of several feline animals have been described 

 from the Loup Fork, one of them (Felis maxima, Scott) 

 being the largest of all known Felidce; but none referred 

 to the genus Machoerodus has been announced. It may, 

 however, yet appear that the F. maxima itself, which Pro- 

 fessor Scott has but provisionally referred to the genus Felis, 

 is a machasrodont. 



The Loup Fork canine incliKles the entire root and neck 

 and the basal portion of the crown. As nearly as it is possible 

 to judge, it represents an animal about as large as the puma, 

 but it must be borne in mind that the size of an animal 

 cannot be very positively and closely estimated from a part so • 

 highly specialized and so subject to variation in the ratio of 

 its size to that of the body as is the canine in this genus. In 

 any event, the tooth indicates an animal smaller than any 

 of the known American Pleistocene species, unless it bo M. 

 gracilis. Cope, and considerably larger than the European 

 Miocene M. pahnidens, de Blainville. 



As compared with the larger American species of Machce- 

 rodus (M. necator, etc.), M. gracilis is characterized by the 

 more compressed form of the basal portion of the upper 

 canine; and this compression is said to be a marked feature. 

 In the Loup Fork species, on the contrary, that tooth has 

 greater relative thickness than in M. necator, the thickness 

 of the tooth, at base of crown, being related to its breadth as 

 1 to 1.65, while the corresponding ratio in M. necator (taken 

 from Cope's illustrations) is 1 to 2.2. In M. neogeeus the 

 ratio, derived from the measurements given by Burmeister, is 

 1 to 3.33. 



The Loup Fork species may be known as Machoerodus 

 crassidens. 



The canine of M. crassidens presents a gentle curvature 

 and has its posterior cutting edge compressed and denticu- 

 lated. Whether the anterior border was of similar character 

 is uncertain. The form of a point-like downward prolonga- 

 tion of the surface of fracture on the anterior border of the 

 crown may have been determined, when the tooth was broken, 

 by the presence of a compressed border, but, if so, the con- 

 tour of the preserved part of the crown does not indicate it. 

 It is, at least, certain that a denticulate carina did not extend 

 so far from the apex on the anterior as on the posterior bor- 

 der. 



DIMENSIONS. 



Inches. 



Breadth of crown of canine at base 1.14 



Thickness of same 69 



Breadth of crown 1.5 inches above base (about) S3 



Thicknt S3 of crown at same (about) 46 



Ler gth of root of caulne (to origin of denticulated keel) 2.44 



Length of canine, as restored (approximate) 5.45 



Should new material prove that only the posterior margin 

 of the canine is denticulated, the species would, in this re- 

 spect, resemble the Machoerodus nestianus of the upper 

 Pliocene of Italy. F. W. Cragin. 



Colorado Springs, Co.'. 



NOTES AND NEWS. 



A NEW SABRE-TOOTHED TIGER FROM THE LOUP 

 FORK TERTIARY OF KANSAS. 

 In a collection of Loup Fork Tertiary fossils obtained by 

 the writer from northern Kansas, is a right upper canine of 

 Machoerodus, apparently different from that of any of the 

 known species of that genus. 



The Pennsylvania State Board of Health, at the instance of 

 the Governor of Pennsylvania, has issued an invitation to the 

 other State and the more important city boards of health, and to 

 the American Public Health Association, to join in a conference 

 with the officers of the World's Columbian Exposition at the city 

 of Chicago, with the view to making an exliibit of the objects, 

 methods, and results of the work of sanitary o£Scials in this 

 country. 



— Mr. Charles S. Peirce has tendered his resignation as Assist- 

 ant in the United States Coast and Geodetic Survey, to take effect 

 Dec. 31. Jlr. Peirce was first attached to the Survery about tliirty 



