56 



SCIENCE. 



[N. S. Vol. IV. No. 80. 



from a mine at Marysville, Montana, which has 

 not only yielded material admitting of excel- 

 lent analyses, conforming to the theoretical 

 composition, but also beautiful crystals. These 

 crystals are shown to belong to the monoclinic 

 system, with an angle of inclination differing 

 but little from 90°, and a rhombohedral sym- 

 metry in the distribution of the faces. In con- 

 nection with this investigation the crystalline 

 form of polybasite was also studied, particu- 

 larly on specimens from Colorado ; and it is 

 shown that they also are monoclinic with the 

 same habit as that which characterizes the pear- 

 ceite. An interesting summary of a number of 

 metallic species among the sulphides, which 

 have a prismatic angle of nearly 60°, is given. 



James L. Greenleaf describes in considerable 

 detail the hydrology of the Mississippi. The 

 special points considered are the volume, flow, 

 the annual rainfall audits distribution, and the 

 relation of flow or run-off to the rainfall, as de- 

 pending upon the special conditions present in 

 a particular case. The discussion is based upon 

 a report by the writer upon certain water powers 

 prepared for the tenth census. The data there 

 given have been amplified to cover the flood 

 and low water as well as the average discharge 

 of the Mississippi and its tributaries, and have 

 been brought up to date by a study of the sub- 

 sequent gaugings conducted by the corps of en- 

 gineers. A series of diagrams present the data 

 graphically and give basis for further discus- 

 sion. The first gives the average dischai'ge for 

 the different tributaries with their branch areas. 

 Another diagram shows the average flow and 

 rainfall, and still another connects the high 

 average and low discharge and rainfall for the 

 upper and lower Mississippi and for the prin- 

 cipal branches. 



C. E. Eastman describes the relations of cer- 

 tain body plates of the Dinichthyids. The sub- 

 ject of Tertiary floras of the Yellowstone Na- 

 tional Park is enlarged upon by F. H. Knowlton. 

 His paper belongs with that on The Age of the 

 Igneous Bocks of the Yellowstone by Arnold 

 Hague, published in the June number. The 

 region is shown to be remarkably rich in species, 

 and three distinct flora are distinguished. The 

 first is referred to the Fort Union or Lower Eo- 

 cene; a second is regarded as Miocene, but older 



than the auriferous, gravels, and the third is 

 regarded as Upper Miocene. The entire flora 

 embraces 147 forms, distributed among 33 natu- 

 ral orders. The remarkable contrast between 

 the richness and variety of the vegetation at 

 that time with the comparative paucity at pres- 

 ent, and the bearings of this upon the change in 

 climate, are brought out. The whole subject 

 will" be developed in detail in a monograph to 

 be published under the auspices of the United 

 States Geological Survey. O. C. Marsh de- 

 scribes a remarkable specimen of a Belodont 

 reptile found in the red sandstone of the New 

 Haven region. His paper is accompanied by a 

 plate showing the portion of the back of the 

 reptile which is preserved. A. E. Verrill gives 

 an article on a new cephalopod of the genus 

 Opisthoteuthis, illustrated by a number of fig- 

 ures. Eemarks are added on the general sub- 

 ject of molluscan morphology. The subject of 

 sepai-ation or isolation in its bearings on geology 

 and zoography is discussed by A. E. Ortmann. 

 He finds in it an explanation of the distribution 

 of animals as well as of the origin of species. 

 T. L. Walker gives observations on percussion 

 figures in mica, and shows that, contrary to 

 what has been hitherto held, the angles between 

 the lines developed are not 60°, but vary some- 

 what widely from this. I. K. Phelps describes 

 an iodometric method for the determination of 

 carbon dioxide. 



PSYCHE, JULY. 



R. A. CooLEY describes and figures on a plate 

 a new structural character in insects, consisting 

 of a ' spiny area, ' a small patch of short sharp 

 spines on the under side of the fore wing near 

 the base posteriorly, related to a corresponding 

 patch on the thorax, at the point which the 

 spines touch when the wings are in repose. He 

 has demonstrated its presence in nearly five 

 hundred moths, all of which fold their wings 

 over the abdomen, and also in some insects of 

 other orders. W. S. Blatchley continues his 

 notes on the winter Coleoptera (sixty species) 

 of Vigo Co., Ind., and A. P. Morse his notes 

 the Tryxalinee of New England, the new genus 

 Clinocephalus being considered. Brief notes 

 on butterflies are given by Miss Soule and 

 Messrs. Folsom and Symthe. 



