98 



SCIENCE, 



[Vol. VI., No. 130. 



different systems proposed for the lab3Tintho- 

 donts, forming a very convenient compilation 

 for the student. The rest of the book is de- 

 voted to descriptions of the different families 

 of the Stegocephali. The author concludes 

 that the paleontological material is still too 

 meagre to venture on a genealogical table, but 

 promises to offer a comparative discussion at 

 the end of the whole work. 



The first part of the second volume con- 

 tains the Dendrerpetondidae, Diplovertebridae, 

 Archaegosauridae, Chauliodontia (Miall), and 

 Melosauridae. In the beginning we find the 

 remarkable note, that it is difficult to accept 

 Cope's division into Rachitomi and Embolom- 

 eri, based on the characters of the vertebrae, 

 because both kinds of vertebrae (rachitomous 

 and embolomerous) can be found in the same 

 animal. The embolomerous form seems to be 

 developed in the caudal, the rachitomous form 

 in the thoracic, region. 



The question whether the hypocentrum or 

 the pleurocentra constitutes the base of the ver- 

 tebra is decided by Fritsch in the following 

 way : A normal vertebra with one centrum 

 never can be formed from a rachitomous ver- 

 tebra, but only an embolomerous vertebra with 

 two disks. The rachitomous form prepares the 

 embolomerous, and it is not surprising that 

 both forms exist in the same animal. 



The following parts will contain the fishes 

 and arthropods, and in the final part the gen- 

 eral conclusions will be given. 



Finall}^ it should be mentioned that galvano- 

 plastic copies of thirty-five Stegocephali have 

 been prepared by the author, which cannot be 

 distinguished from the originals. The}' are ob- 

 tainable at the low price of fift}^ dollars from 

 the author, 35 Brenntegasse, Prague. 



PRACTICAL BOTANY. 



Teachers who carr}' their classes beyond 

 the elements of analytical botan}' find the 

 number of adjuncts at their disposal increas- 

 ing rapidly, so far, at least, as histolog}' is 

 concerned. Beside general text-books of all 

 grades, and the treatises, large and small, on 

 the methods of microscopical work, explicit 

 directions for the study of common represen- 

 tative plants are now published in several lan- 

 guages. 



So far as a short course is concerned, the 



A course of practical instruction in botany. By F. O. Boweu, 

 M.A., F.L.S., and Sydney H. Vines, M.A., D.Sc, F.L.S. Part 

 i, Phanerogamae-Pteridophyta. Locdon, JIacmiilan <& Co., 1885. 

 11+226 p. 16°. 



demand for laboratory directions is already 

 well met by the botanical portion of Huxley 

 and Martin's 'Biology,' which any capable 

 teacher can bring to date by a few lectures, 

 and supplement by s^mopses of work for a few 

 additional plants, like Spirogyra, Aspergillus, 

 and Penicillium ; and it is doubtful if many 

 courses offered in America are comprehensive 

 enough to warrant carrying this part of the 

 work further. Yet to students who have time 

 for additional work in this direction, without 

 the knowledge requisite for carrying it on in- 

 dependently, this little book of Mr. Bower's, 

 which owes its origin to the same causes that 

 produced Huxle}^ and Martin, will prove ex- 

 ceedingly useful. If it cannot be said to equal 

 Strasburger's ' Botanisches practicum,' it has 

 the merit of being in English, and bears evi- 

 dence of careful workmanship on every page, 

 while it is sensibly bound for laboratory use. 



NOTES AND NEWS. 



The vessel Alert, sent to visit the stations es- 

 tablished last summer in and en route to Hudson 

 Bay, has been obliged to return by reason of the 

 prevalence of pack-ice, the exhaustion of their coal, 

 and certain damages sustained. She will start again; 

 but those interested in the commercial route via 

 Hudson Bay to Manitoba are much disappointed; 

 and the return is generally regarded as evidence that 

 such a route would be even more precarious and un- 

 certain than its opponents have claimed. 



— Dr. Elkin, in charge of the heliometer of the 

 Yale-college observatory, has been engaged for nearly 

 a year and a half past in measuring the group of the 

 Pleiades, his original plan being to measure with this 

 instrument the same stars which Bessel measured 

 with the Konigsberg heliometer about fifty years ago. 

 Dr. Elkin has taken advantage of all the improve- 

 ments in the instrument and the methods of using it 

 which have been developed in the last half-century; 

 and, in addition to the successful carrying-out of his 

 carefully elaborated plan of triangulation, he has also 

 been able to extend his work to a large number of 

 stars which Bessel did not measure. The position- 

 angle and distance of the Bessel stars from the large 

 star Alcyone are included in the work. The results 

 of this very valuable work cannot be fully discussed, 

 and prepared for publication, until the positions of 

 certain stars of reference have been obtained from the 

 work of other observatories where they are now being 

 determined. Dr. Elkin has also obtained measures 

 of the distances of a number of craters on the moon 

 from neighboring stars, on thirty-six nights, near the 

 times of first and last quarter. The positions of these 

 craters on the moon itself have been determined; also 

 series of measures made of the diameters of Venus, of 

 the outer ring of Saturn, and of the satellite Titan 



