Mabch 23, 1883.] 



SCIENCE. 



195 



modern streams. Its plateau character is not 

 given b}' a continuous stratum of hard rock 

 parallel to the general surface, but has been 

 produced by the uniform erosion of a sj'stem 

 of plicated strata. Snch uniform erosion 

 could only have been accomplished by streams 

 flowing at a low angle. Second, the eastern 

 boundary- of the range or plateau is a line of 

 faulting ; and the orographic movement pro- 

 ducing the range consisted of a displacement 

 along this fault-line, and a consequent inclina- 

 tion of the plateau-like mass to the westward. 

 That this movement belongs to late geologic 

 historj' is strongly indicated by the fact that 

 it is incomplete. Some unpublished observa- 

 tions b}- Mr. I. C. Russell show that a part of 

 it has occurred since the date of the quater- 

 nar}' lakes of the Great Basin ; aud the Inyo 

 county earthquake brings it down to 1872. 



If a rise of temperature is not favorable to 

 glaciation, if a fall of temperature does not 

 make deserts drier, and if river-terraces are 

 not indicative of waning precipitation, it might 

 seem that our author's theory is badlj" off; but 

 the case is not hopeless. The paleonto logic 

 evidence, and the doctrine of the dissipation 

 of solar energy, remain ; and if he will now 

 devote himself to the investigation of the gla- 

 ciers that are known to have recentl}- increased, 

 to the dry countries in which civiHzation and 

 wealth have supplanted barbarism aud poverty-, 

 and to the rivers that are engaged in filling up 

 the vallej's they once excavated, he may yet 

 find in recent history the evidence he seeks of 

 a secular change. G. K. Gilbert. 



tic the Indian Ocean, and the Mediterranean. 

 Thej^ bear a close resemblance to the Trachy- 

 nemidae ; but they are furnished with great 

 numbers of ambulatory tentacles, whicli are 

 wonderfully like the sucking-feet of echino- 



DEEP-SEA MEDUSAE. 



Report on the deep-sea Medusae dredged by li. M. S. 

 Challenger during the years 1873-76. By Prof. 

 Ernst Haeckel. London, 1882. 105 + 154 p , 

 32 pi. 4°. 



The expedition obtained only eighteen Me- 

 dusae from deep water ; and some of these, 

 such as the beautiful Margelid, shown in plate 

 1, are undoubtedly surface-forms. But the 

 value of the collection must not be estimated 

 by its size : for some of the species are very 

 primitive forms, or ancestral types, and are 

 therefore of the greatest scientific interest ; 

 while others present unique and remarkable 

 modifications of structure to adapt them to 

 their life on the bottom. 



Among the latter are the Pectyllidae, — a new 

 family established by Haeckel, to include three 

 genera of Medusae, obtained by the Challenger 

 at a great depth in the Arctic Ocean, the Antarc- 



Teseernntha connectens in profile, ten times the natural size. 

 Outline-sketch from Haeckel's Deep-sea Medusae. PI. 15. 

 Fig. 1. 



derms, terminating, like these organs, in ex- 

 panded sucking-disks. As Haeckel has ob- 

 tained living specimens of the Mediterranean 

 species, and has thus been able to supplement 

 his account of the anatomj' by observations of 

 the living animal, we have an interesting ac- 

 count of its habits in confinement. He says 

 that it usually lies on its back, extends a por- 

 tion of its sucking-feet stifHj^ out around it, 

 and thus attaches itself to the bottom of the 

 glass : the other sucking-feet play freelj^ in the 



