May 22, 1879] 



NATURE 



8 



they have their largest development, but do not correspond 

 merely to the paired bones of the lizard and platypus, 

 being formed both of cartilage and bone as in the bird. 

 The girdle of the hind-limb is of a more archaic and less 

 metamorphosed pattern than that of the fore-limb ; in 

 man the pelvis corresponds very closely with the shoulder- 

 girdle of the frog. The limbs agree nearly with the 

 tailed amphibian pattern. The main modification of the 

 spine is seen in the presence of inter-central pads or 

 buffers of cartilage, and a pair of bony epiphyses to each 

 centrum. 



The skull is wrought into one strong, compact building, 

 and the short, solid, lower jaw is articulated directly to 

 the head ; the primary lower jaw stops growing at a very 

 early period of embryonic life, and then loses, by absorp- 

 tion, the Meckelian rod, which is, indeed, all the arch 

 except its upper part ; the working mandible is formed 

 from superficial bone and cartilage, the prototypes of 

 which must be sought amongst the lowest fishes. The 

 upper part of the primary mandibular arch, which in the 

 lower types gives rise to the quadrate, is now specialised 

 to form the malleus, or the outermost bone of the chain 

 of the middle ear. One principal external bone and some- 

 times an imperfect rudiment of one or two others appears 

 on the inside of the primary lower jaw in the embryo, but 

 these enjoy a very short separate existence. In the hyoid 

 arch the upper element, or epi-hyal, is divided off to form 

 the incus, the middle bone of the middle ear. The orbi- 

 culare is a further subdivision of the upper element, and 

 the stapes is a part of the auditory capsule segmented off. 

 The cochlea, which, in the Sauropsida, forms only part of 

 a coil, is now perfected into a spiral chamber with several 

 turns. The membrane of the drum lies at the bottom of 

 a long tube, and is there stretched upon a bone which at 

 first is a mere imperfect ring, but which afterwards grows 

 out as the bony jtieatus externus. The co?icha auris is an 

 opercular cartilage of the first cleft, the essential part of 

 which is the tragus. 



Outside the primary lower jaw, the two halves of which 

 are confluent in front and below, there is a cartilage 

 having the same relations as the labial of a shark ; in the 

 outside of this cartilage the dentary splint bone appears, 

 and gradually converts it into bone, from before back- 

 wards. Throughout life part of this cartilage still remains, 

 capping the convex hinge of the lower jaw; it is probable 

 that the cartilaginous plate within the joint (?neniscus')?LT\'\ 

 the cartilage lining the temporal bone above, to finish the 

 joint, are derived from the same source. 



As already mentioned, the forecast of the mammalian 

 type, which is very plain in the cartilaginous fishes, be- 

 comes much more plain, definite, and indubitable in the 

 frog and toad. In fact, the building materials are passed 

 from hand to hand, as it were, in this Way : the batra- 

 chian forefathers brought down all things meet for the 

 work, borrowing and taking cartilages from the Sela- 

 chians, and bones from the Ganoids, and noiselessly 

 forming them, after due selection, into a new, more com- 

 pounded, and nobler structure. 



The rude ancestors of the tribes that give suck began 

 to build on this higher level, with these more varied or 

 better-shaped blocks and plates ; and by the infinite cun- 

 ning, the effectual working of the morphological force, in 

 due time the consummation was effected of vertebrate 

 form. But the consummation of all, the election and 

 selection, that has been going on since the beginning of 

 the ages, is seen in man, who alone gives meaning to, 

 and reads the meaning of, the whole mystery of organic 

 life. 



OUR ASTRONOMICAL COLUMN 



TheObservatorvof Mannheim. —We have received 



from Prof. Valentiner, the successor of Prof. Schonfeld 



in the direction of the observatory at Mannheim, the third 



part of the "Astronomical Observations" issued from 



this establishment. The two former parts, published in 

 1862 and 187s, contained observations of nebulae and 

 clusters, but without micrometrical measures of the posi- 

 tions of the components of the latter objects ; m the 

 present part the two clusters Nos. 1166 and 4410 of Sir 

 John Herschel's General Catalogue are specially treated 

 upon, and the position of thirty-six stars in the former 

 cluster and seventy-one stars in the latter have been de- 

 termined by micrometrical reference to a number of stars 

 the places of which have been fixed by meridian obser- 

 vations. In this work a filar-micrometer upon the Stein- 

 heil refractor has been employed, and both observations 

 and reductions have been made with every care to secure 

 a high degree of precision. Diagrams of the stars 

 observed in each cluster are appended. It is intended 

 to measure the clusters 1454 and 11 19 of the General 

 Catalogue in the same manner. Only by patient and 

 accurate measures of this nature can we hope eventually 

 to learn the internal structure of these systems. Prof. 

 Valentiner has given full details of his observations and 

 reductions, which may be advantageously consulted by 

 any one proposing to enter upon similar work. The 

 Mannheim Observatory not possessing a meridian-circle, 

 he has had recourse to the assistance of other observa- 

 tories — Berlin, Leyden, and Leipsic — for the accurate 

 determination of the positions of his reference-stars. 



Tempel's Comet. — M. Raoul Gautier has circulated 

 an ephemeris of this comet, founded upon a correction of 

 his predicted elements from three observations by Dr. 

 Tempel at Arcetri. The positions for May do not ma- 

 terially differ from those which have appeared in NATURE. 

 The corrected orbit is as follows : — 



Perihelion passage 1879 May 7 '02 M.T. at Berlin. 



Longitude of perihelion ... 238 11 30-1 ) From mean eqninox 



,, ascending node 78 45 37'4 ( l879'0 



Inclination 9 46 3i"6 



Angle of excentricity 2735 o'6 



Mean daily motion 593"' '8 



Log. semi-axis major o'5i788o 



The Minor Planets. — From the Berliner Astrono- 

 ;;«V//e'jy(Z.4ri5«i:/2 for 1 881, whichis just published, it appears 

 that of the 194 small planets discovered up to the end of 

 March last, eighteen have been observed at only one 

 opposition, one of the number being Medusa, which, if 

 the elements so far determined can be relied upon, has a 

 shorter period of revolution than any other member of 

 the group. Flora coming next. Upwards of 150 pages 

 are devoted to the elements and ephemerides of these 

 I bodies for 1879, forming the speciality of this publication, 

 j upvifards of forty calculators in various parts of Europe and 

 ' America taking part in this laborious work ; seventy-one of 

 the ephemerides are by Dr. Maywald, of Berlin, who has 

 been long similarly occupied. As already stated this 

 portion of the Berliner Jahrbuch has been sent out to 

 observers in anticipation of the appearance of the volume. 

 The circulars independently issued by Prof. Tietjen have 

 kept astronomers informed as to elements and positions 

 of the newly-discovered bodies. 



Prof. Peters, of Clinton, New York, announces his 

 detection of a planet which, if new, will be No. 196. 



I The Occultation of Venus on August 20.— On 

 I this date Venus, then at her greatest brilliancy, and so of 

 ! crescent-form, will be occulted by the moon, which is also 

 a narrow crescent at the time. The phenomenon would 

 be one of much interest were it not that it is visible in a 

 dark sky, only in the South Atlantic. If we calculate for 

 the Royal Observatory, Cape of Good Hope, we find that 

 the immersion takes place at 8h. 44m. mean time, but the 

 planet will have set about five minutes previously, and m 

 other parts of the South African Colonies, the occultation 

 is similarly invisible. At St. Helena there will be no 

 occultation. 



