November 1, 1895. ] 



SCIENCE. 



bib 



crista trochanteriea, linea aspera, angulus 

 medialis, &c. Of the human femora exam- 

 ined, one showed all four peculiarities of the 

 Javan specimen, so that he doubted whether 

 the latter differed from a human femur. 

 He also doubted the reference of the skull 

 and explained why he did not believe that 

 Pithecanthropus had an erect gait. He would 

 like to have these bones compared with 

 those of the New World monkeys. 



Prof. Martin (Ley den) stated that the age 

 of these bones could only be late Pliocene 

 or early Pleistocene. 



Sir William Flower laid much stress upon 

 the correspondence between the skull of 

 Pithecanthropus and that of Hylohates. 



Dr. Bashford Dean (New York) spoke 

 ' On the Embryologj^ of the North American 

 Ganoids, Accipenser, Lepidosteus and Amia,' 

 and exhibited a number of specimens illus- 

 trating their embryonic and larval develop- 

 ment. A comparative study of these forms 

 emphasizes the results of the palaiontologist 

 as to the phylogeny of the Teleosts, i. e., 

 their descent from a series of transitional 

 Mesozoic Ganoids, as Leptolepids, Caturids; 

 it interprets also the difficulties of the em- 

 bryology of the Teleost, e. g., the origin 

 of the periblast, the mode of grastulation, of 

 blastulation, the significance of Kupflfer's 

 vesicle, of the solid neural axis, and of the 

 specialized origin of the mesoderm. In a 

 series of diagrams of saggital sections of 

 early and late grastulse there was shown 

 on the screen a more detailed comparison; 

 thus in Lepidosteus shark like features were 

 apparent, the conditions of the develop- 

 ment of the germ layers of ventral and 

 dorsal lip were closely similar, and by the 

 time of the blastopores closure the ap- 

 pearance of the embryo was hardly to 

 be noted. In Amia, on the other hand, the 

 precocious character of the development of 

 the embryo was extremely notable, form- 

 ing clearly marked transitional conditions 

 to the Teleosts. 



At 2 P. M. was held the third and last ses- 

 sion of the full Congress, when Mr. John 

 Murray (Edinburgh) delivered a lecture 

 upon ' Deep Sea Explorations.' He showed 

 the respects in which our knowledge of the 

 great ocean depths and of their animal life 

 has so greatly increased in the last 40 years, 

 and that the biological sciences have 

 reaped the chief benefit of such increase. 

 The greatest measured depth in the sea is 

 8500 metres, the mean depth 4500 metres. 

 About 5 per cent of the deep part is 5500 

 m. or more. Mr. Murraj' then gave an ac- 

 count of the investigation of the bottom de- 

 posits undertaken by himself and M. Re- 

 naud, of Brussels, which had led to such 

 important results. The question of tem- 

 perature was then taken up. This varies 

 at the surface from 28° at the equa- 

 tor to 0° at the poles ; at the bottom the 

 water has a temperature almost everywhere 

 equal and constant, averaging 3°. It is es- 

 pecially remarkable that in the tropics the 

 number of deep sea species is much greater 

 than in temperate regions, but in the latter 

 the number of individuals of each species is 

 far larger. The speaker then considered 

 some of the characters of deep-sea animals. 

 We have not succeeded in finding animals 

 which can be considered representatives of 

 extinct faunas. The forms are distinct ; 

 they are often of considerable size, they 

 carry phosphorescent organs and usually 

 have no striking colors ; but on the whole 

 they resemble animals from less pro- 

 found depths. A very curious point is the 

 resemblance between the deep sea forms of 

 high latitudes, north and south. This was 

 explained by assuming that the bottom had 

 formerly the same fauna everywhere. The 

 temperature was then uniform and a rich 

 flora flourished at the poles, as at the equa- 

 tor. At that time the sun did not give out 

 much more heat than at present, but its 

 radiating surface was far larger, and there- 

 fore the distribution of solar heat ujjon the 



