76 Scientific Intelligence. 



York. These specimens and the others in Rochester have afforded 

 Prof. Allen material for his paper, which is illustrated by four 

 plates. The same number of the Bulletin contains a paper by 

 Prof. Allen on Squalodont Remains from Charleston, S. C, with 

 two plates. 



4. Selected Morphological Monographs, by members of the 

 Johns Hopkins University; Edited by W. K. Brooks, Ph.D., 

 Director of the Chesapeake Zoological Laboratory. — This vol- 

 ume, in 4to., contains four papers, of high merit, which have 

 already appeared elsewhere ; W. K. Brooks on Lucifer, a study 

 in morphology, with 11 plates; on the Life History of the Hydro- 

 Medusas, a discussion of the origin of the Medusas and the signifi- 

 cance of Metagenesis, with 8 plates ; and on the Stomatopoda, 

 with ] 6 plates ; and by E. B. Wilson, on the development of 

 Renilla, with 16 plates. Only 100 copies published. Price, $7.50 

 each, postage or express charges included. 



No. 8, vol. iii, of the Studies from the Biological Laboratory of 

 the University contains a contribution to the Embryology of the 

 Prosobranch Gasteropods, by J. P. McMurrich, with 4 plates, and 

 on the anatomy and development of the Salpa-chain by W. K. 

 Brooks, with 2 plates. 



IV. Astronomy. 



1. Transactions of the Astronomical Observatory of Yale 

 University. Vol. I, Part I ; New Haven, 1887, 4°, pp. 105. — The 

 first piece of work undertaken by Dr. Elkin on taking charge of 

 the Yale Heliometer in 1884 was the determination of the relative 

 positions of those stars of the Pleiades which were bright enough 

 to be measured by the instrument. This work has occupied the 

 larger portion of his time during the last three yeai's, and the 

 present memoir is the outcome of it. 



The stars measured were all of the stars in the Bonn Durch- 

 mustering down to the 9*2 magnitude, sixty-nine in number, 

 which were in the dense part of the Pleiades group. One of the 

 first undertakings of Bessel with the Konigsberg Heliometer was 

 the measurement of this group. He included 53 stars, one of 

 which was, however, omitted by Dr. Elkin as being too faint. 

 A comparison of two such measurements made with an interval of 

 45 years seemed likely to give results interesting and valuable of 

 themselves. At the same time the methods employed were such 

 as to furnish severe tests of the instrument, and to give due con- 

 fidence to future properly conducted measures that shall be made 

 with it. 



Two separate and entirely distinct series of measures have been 

 made. The first here presented was in time the second under- 

 taken, being the measurement of the position, angles and distances 

 from Alcyone. This was Bessel's method. It was not employed 

 by Dr. Elkin until experience gave him confidence in the position 

 angles determined by the instrument. The second was a system 



