450 



NATURE 



[March io, 1892 



SCIENTIFIC SERIALS. 



American Journal of Science, February.— On the use of 

 a free pendulum as a time standard, by T. C. Mendenhall. 

 The accuracy with which we measure hours, minutes, and 

 seconds is dependent upon our ability to subdivide the sidereal 

 day by mechanical arrangements, e.g. chronometers and clocks. 

 The author believes that a free pendulum, vibrating under con- 

 stant conditions, furnishes a much more trustworthy standard for 

 short intervals of time than any clock or chronometer. To 

 determine the period of such a pendulum, a small mirror is 

 placed in a vertical plane on the pendulum head, and another 

 is placed parallel to it, but rigidly attached to the support upon 

 which the pendulum swings. At a distance of about a metre, 

 an apparatus is arranged which illuminates a slit at intervals of a 

 second. Each of the two mirrors reflects images of the illu- 

 minated slit to an observing telescope, and the arrangement is 

 such that when the pendulum is at rest, or at its lowest point, 

 the two images just overlap. Suppose this overlapping to be 

 observed at any instant, then, if the chronometer which makes 

 the current for the illumination of the slit, and the pendulum, 

 have the same period, or if they differ by half a period, the same 

 appearance would be observed continually. But if the two differ 

 by an extremely small amount, the image from one of the 

 mirrors will be a little above or below the image of the other 

 when the slit is illuminated, and the distance separating them 

 will go on increasing until the pendulum has gained or lost one 

 oscillation. Such a pendulum and accessories can be used to 

 compare one chronometer with another or with a clock. And 

 the great advantage it possesses is that in an hour or less a 

 daily rate can be determined, correct to about three-hundredths 

 of a second. — On the Bear River formation, a series of strata 

 hitherto known as the Bear River Laramie, by Dr. Charles H. 

 White. — The stratigraphic position of the Bear River firmation, 

 by T. W. Stanton. The object of these two articles is to show 

 that the strata which have hitherto been known as Bear River 

 Laramie are not only not referable to the Laramie formation, 

 but that they occupy a lower position, being overlain by marine 

 Cretaceous strata the equivalents of which are known to 

 underlie the true Laramie. — The iron ores of the Marquette 

 district of Michigan, by C. R. Van Hise. — An illustration of 

 the flexibility of limestone, by Arthur Winslow. — The separa- 

 tion of iron, manganese, and calcium, by the acetate and 

 bromine methods, by R. B. Riggs.— The Central Massachusetts 

 moraine, by Ralph S. Tarr. — Proofs that the Holyoke and 

 Deerfield Trap sheets are contemporaneous flows, and not 

 later intrusions, by Ben. K. Emerson. 



The Quarterly Journal of Microscopical Science, vol. xxxiii., 

 Parti (December 1891), contains : — Dr. Marcus M. Hartog, 

 Some problems of reproduction : a comparative study of gameto- 

 geny and protoplasmic senescence and rejuvenescence (pp. 

 1-80). This important paper cannot be summarized within the 

 space at our disposal ; the table of contents runs to two pages, 

 and the theses which state concisely the results of the inquiry 

 are twenty in number, extending over three pages. — Herbert E. 

 Durham, On wandering cells in Echinoderms, &c., more espe- 

 cially with regard to excretory functions (plate i.). Following 

 up his researches on the emigration of amoeboid corpuscles in 

 starfish, the author of this paper inquires as to the subsequent 

 fate of the pigment-containing corpuscles in other animals, 

 selecting Dytiscus inarginalis for this purpose. In the irregular 

 Echinids the process of removal of products from the body by 

 means of amoeboid cells was seen to be more definitely asso- 

 ciated with pigment ; these wandered out at any point of the 

 free surface of the body, in the neighbourhood of the circumoral 

 rosette feet, and in the feet themselves, or into the tubes of the 

 madreporite. In the consideration of this subject the great 

 importance of these two processes— the reaction to minute 

 foreign bodies, and the use of the wandering cells in getting rid of 

 effete material from the system — are insisted upon, and numerous 

 weighty and important facts are detailed. In notes on Echino- 

 derm histology the dorsal organ is minutely described, and its 

 functions are detailed. — Sidney F. Harmer, On the nature of 

 the excretory processes in marine Polyzoa (plates ii. and iii.). 

 A series of interesting investigations, made at the Zoological 

 Station at Naples, go to confirm the view that the marine 

 Ectoprocta are not provided with definite nephridia ; and appear 

 to show that the excretory processes are carried on principally 

 by the "brown bodies," the funicular (connective) tissue, and 

 the free mesoderm cells contained in the meshes of the latter. — 

 J. T. Cunningham, Spermatogenesis in Alyxine glutincsa (plate 

 NO. II 67, VOL. 45] 



iv.). These investigations as to the development of the sper- 

 matozoa in this hermaphrodite fish were carried on at Alver' 

 strommen, some twenty miles to the north of Bergin. The 

 author confirms in great measure his previous work, but he 

 failed to find fertilized ova.— Dr. W. Blaxland Benham, Notes 

 on some aquatic Oligochseta (plates v. to vii.). We have 

 notes on the anatomy and histology of Heterochccta costata, 

 C laperede ; a note on Spirosperma ferox, Eisen ; on a species 

 of Psammoryctes ; note on the chetse of Tubifex rivulorum ; 

 on Stylodrilus vejdovskyi, n. sp., found just below Goring-on- 

 Thames ; note on Nais elinguis ; on the supposed constancy of 

 n in a given species of Naid, n being the position of the zone 

 of budding, the numbers following signifying the number of 

 segments in front of the zone. — Charles Slater, on the differ- 

 entiation of leprosy and tubercle bacilli. As any staining agent 

 which will colour the leprosy bacillus will also stain the tubercle 

 bacillus, the methods proposed to stain the one leaving the 

 other unstained are untrustworthy, and the apparent differences 

 in respect to rapidity of staining and resistance to decolorization 

 are due to difference in numbers of bacilli present. — Charles 

 Stewart, On a specimen of the true teeth of Ornithorhynchus 

 (plate viii.). 



Part 2, January 1892, contains :— Arthur E. Shipley, On OncA- 

 nesoma steenstrupii (plate ix. ), describes the minute anatomy of 

 this the smallest Sipunculid known, one of three species, all of 

 which have been described from the north-west coast of Nor- 

 way. The head is much simplified ; the lip surrounding the 

 mouth bears no tentacles, but is produced dorsally into a blunt 

 ciliated process ; there are neither tentacles, hooks, collar, pig- 

 mented skin, or eyes ; there is no vascular system, no spindle 

 muscle, and no giant cells are found in the brain, v/hich latter is 

 not bilobed. The retractor muscle is single, arising from the 

 posterior end of the body ; the nephridium is also single. 

 Nothing is known as to its development. — Edward A. Minchin, 

 Note on a sieve-like membrane across the oscula of a species of 

 Leucosolenia, with some observations on the histology of the 

 Sponge (plates x. and xi.). In a species of Leucosolenia, 

 probably L. coriacea, found at Plymouth, a thin perforated 

 membrane was found stretching across the oscular openings. 

 This membrane occurs a little below the actual margin of the 

 opening, varies in size with the oscula, but is imperforate in the 

 very smallest openings ; it is composed of two layers of cells in 

 apposition ; these are separated by a thin layer of jelly. The 

 author suggests an analogy between this membrane and the 

 well-known sieves in some of the Hexactinellid Sponges, and 

 severely criticizes Von Lendenfeld's homologies concerning 

 oscular sieve plates. Some new points about the ectoderm and 

 endoderm are alluded to. — Ernest W. MacBride, The develop- 

 ment of the oviduct in the frog (plates xii.and xiii. ). The author 

 states the principal new points as follows: (i) the oviduct 

 arises opposite the first and not the third nephrostome 

 of the pronephros ; (2) the whole of the duct and not 

 merely its posterior half, as Hoffman supposed, arises ap- 

 parently by proliferation from a strip of modified peritoneum, 

 entirely independent of the Wolffian duct ; (3) the lumen appears 

 quite close to the peritoneum and in patches. — Margaret Robin- 

 son, On the nauplius eye persisting in some Decapods (plate xiv. ). 

 The nauplius eye has been described as persisting in Schizopods, 

 and has been referred to by Dr. Paul Mayer as occurring in 

 Palaemonsetes, but the author describes and figures it as found 

 by her in several species of Decapoda, Pandalus annulicornis, 

 Virhius 7'arians. As regards the shape of the pigment 

 cells, the position of their nuclei, and the arrangement of 

 the nerve end cells in three groups, these eyes exactly resemble 

 the median eye of Branchipus as described by Claus. — Dr. W. 

 Blaxland Benham, Notes on two Acanthodriloid Earthworms 

 from N^w Zealand (plates xv. and xvi. ), describes Plagiochceta 

 punctata, n. gen. et. sp. ; this new genus has apparently 

 afiinitieswith Perichteta and with Acanlhodrilus. Also describes 

 Neodrilus nionocystis, Beddard. — Asajiro Oka and Arthur Willey, 

 On a new genus of Synascidians from Japan (plates xvii. and 

 xviii.). This remarkable Compound Ascidian was found in some 

 quantities at Moroiso, a place on a small bay to the north of 

 Misaki, some fifty miles south of Tokio. It belongs to the 

 Didemnidse, and has been called Sarcodidemnoides misakiense. 

 The colour is a brilliant red, and the surface .of the colony is 

 smooth and glistening; at the tips of the round knob-like 

 lobes, which are a very characteristic feature of the genus, are 

 seen the small but extinct excurrent orifices, the lips of the pores 

 being slightly raised above the level of the surrounding surface. 



