316 



SCIENCE. 



[N. S. Vol. IX. No. 218. 



a remarkable vertebral series extending 

 from the 5th dorsal to the end of the tail : 

 (1) The center of motion is the sacrum, 

 where three vertebrte are completelj^ coa- 

 lesced to the summits of the spines, besides 

 a fourth rib-bearing sacral with a free 

 spine. The sacro-iliac union is by means of 

 both ribs and neuropophysial plates. The 

 presence of such plates in all the anterior 

 caudals, as first described by the writer, 

 proves that the sacrum is reenforced by 

 additions from the anterior caudals. (2) 

 There are more than thirty caudals and 

 three distinct types of chevron, instead 

 of the single tj'pe to which Marsh ap- 

 plied the generic name Diplodomis. The 

 tail was undoubtedly a powerful swimming 

 organ and also a lever by means of which 

 the anterior portion of the body was ele- 

 vated, the acetabulum serving as a fulcrum, 

 while the trunk was immersed in water. 

 This power did not exist upon land as in 

 the Iguanodontia. 



Tlie Osdeula Auditus of the Mammalia. J. S. 



KiNGSLEY and W. H. Rdddich. 



Studies on embryo pigs and rats show 

 that the incus is the quadrate, the malleus, 

 the proximal end of Meckel's cartilage. 

 These cannot be homologized with the 

 columellar chain of Sauropsida, since they 

 are in front of the spiracular cleft and in 

 front of the chorda tympani, while the 

 columella is behind the spiracle and 

 chorda tympani. The incus (quadrate) 

 articulates with the stapes in the mam- 

 mals, exactly as is the case in the urodeles. 

 Nothing similar occurs in the Saurop- 

 sida. This is regarded as additional evi- 

 dence that the mammals have had an am- 

 phibian ancestry. The quadrate cannot 

 have disappeared in the glenoid fossa, as 

 maintained by Albrecht and Cope, as this 

 would involve a translation of parts impos- 

 sible to explain. The mammalian lower 

 jaw articulates by means of the dentary 



rather than by means of the articulalare, 

 i. e., its articulation is not homologous with 

 that in lower groups. A longer summary 

 of the paper will appear in the American 

 Naturalist for March. 



Notes on 3Iammalian Embryology. C. S. Mi- 

 NOT. (Read by title.) 



Professor 0. van der StrichVs Researches on the 

 Human Ovum. C. S. Minot. (Read by 

 title.) 



Notes on the Morphology of the Chicle Brain. 

 S. P. Gage. 



A Specific Case of the Elimination of the Unfit. 



H. C. BuMPUs. 



The results of a comparative study of one 

 hundred and thirty-six English sparrows, 

 which were rendered helpless or actually 

 perished during the severe storm of Feb- 

 ruary last, was numerically expressed, and 

 it was shown that there was not only a 

 measurable but a striking physical differ- 

 ence between the birds which actu.ally suc- 

 cumbed and those which survived the storm. 

 The birds which perished were longer, 

 heavier, possessed of shorter heads, shorter 

 leg bones, of less breadth of skull and of 

 reduced sternum, while those which sur- 

 vived tended toward the possession of char- 

 acters opposite to these. 



While these average differences between 

 the two groups of birds were emphasized, 

 attention was also called to the fact that the 

 individuals of extreme variability occurred 

 most frequently among the birds which per- 

 ished. The longest bird and the shortest 

 bird in the entire collection perished. The 

 same is true of the one having the greatest 

 and the one having the least alar extent. 

 The heaviest bird died ; the one with the 

 longest and the one with the shortest head 

 died, and the one with the shortest humerus, 

 the one with the longest femur, the one with 

 the longest and the one with the shortest 

 skull, and the one with the shortest keel to 



