May 10, 1888] 



NATURE 



47 



acid : namely, H,Se0 2 NH 2 . It is unstable, continuously 

 evolving ammonia, and ultimately becoming a stable acid salt, 

 N 1 1 ,, 1 1 . Se( ) 2 N H„) 2 . 1 'he neutral salt forms hexagonal prisms 

 and pyramids, and the acid forms prismatic crystals. The 

 neutral salt dissolves in 116 parts of alcoholic ammonia, but is 

 decomposed by absolute alcohol or by water. 



April 26. — "On the Modifications of the First and Second 

 Visceral Arches, with especial Reference to the Homologies 

 of the Auditory Ossicles/' By Hans Gadow, Ph.D., M.A , 

 Strickland Curator and Lecturer on Comparative Anatomy in 

 the University of Cambridge. Communicated by Prof. M. 

 Foster, Sec. R.S. 



The phylogenetic development of the first two visceral arches 

 shows us some most interesting changes of function, which we 

 can follow upwards from the lower Selachians to the highest 

 Mammals. 



Originally entirely devoted to respiration as gill-bearing 

 structures, the whole hyoidean arch becomes soon a factor in 

 the alimentary system. Its proximal half forms the hinge of the 

 masticatory apparatus, its distal half remains henceforth connected 

 with the process of deglutition. Then this suspensorial arrange- 

 ment is superseded by a new modification ; the hyomandibula is 

 set free and would disappear (it does nearly do so in Dipnoi and 

 certain Urodela), unless it were made use of for a new function ; 

 with its having entered the service of the conduction of sound, 

 it has entered upon a new departure, and it is saved from de- 

 generation. The whole system of the on? to four elements of 

 the middle ear, which all have the same function as conductors 

 of sound, is to be looked upon as one organ of one common 

 origin, — namely, as a modification of the hyomandibula, the 

 primitive proximal paramere of the second visceral arch. 



Successive Modifications of the Mandibular and Hyoidean 

 Visceral Arches. 



I. Primitive condition (Notidanida;). The palato quadrate 

 bar alone carries the mandible. The second arch is indifferent. 

 Hyomandibula and quadrate (the palatine part is an outgrowth) 

 are both attached to the cranium. 



II. The hyomandibula .gains a fibro cartilaginous connection 

 with the mandible, the masticatory apparatus becomes amphi- 

 slylic and occasionally hyostylic (Rajidrc, most S Jachians). 



The hyoid gains a cranial attachment (many Rajida). 



HI. The quadrate or autostylic suspensorium becomes pre- 

 ponderant ; the hyomandibula is, as in Teleosteans, divided into 

 a proximal and into a distal (symplectic) element. The proximal 

 part is received into a fenestra of the otic capsule, and is con- 

 verted into a stapes, whilst the distal half either remains {Proteus, 

 Siren, Menopoma) or is lost (other Urodela). The whole hyo- 

 mandibula would have been lost owing to its excalation from 

 suspensorial function^, unless it had entered the auditory 

 service. 



IV. The autostylic arrangement prevails. The whole hyo- 

 mandibula remains, gains an attachment on the "tympanum" 

 and differentiates itself into several conjointed pieces, notably 

 stapes or columella proper, and extra-columella or malleus. 



The extra-columella gains connection with the parotic cartilage ; 

 this connection frequently remains, but in A nura alone itconatins 

 a special element of probably parotic origin. 



The quadrate forms an important part of the tympanic 

 frame. 



IVrt, Collateral departure of the Anura. The connection 

 between the tympanal part of the hyomandibula with the 

 mandible is lost. 



V. The quadrate still forms the principal suspensorial part of 

 the mandible. The extra-columella, or malleus, retains for a long 

 time its previously acquired connection with Meckel's cartilage 

 {Amniota). 



\'a. The top end of the hyoid is attached to the cranium 

 (Geclzos, Mammalia), and is occasionally fused with the extra- 

 columella (Hatter id). 



\ /'. Or, the proximal portion of the hyoid is removed from 

 the skull and remains otherwise well developed (most Lizards) ; 

 or its proximal portion becomes reduced and lost (Chelonia, 

 Crocodiha, Ophidia, Aves). 



V c. The extra-columella gains an attachment to the quadrate, 

 squamosal, or pterygoid, whilst its connections with the mandible 

 (Ophidia, Chama'leon), and the tympanum, are lost. 



\ I. The quadrate gradually loses its articulation with the 

 mandible ; the latter gains a new outer articulation with the 

 squamosal ; the quadrate acts almost entirely as a tympanic 



frame. Incus and malleus fuse sometimes with each other, and 

 lean on to the parotic region. The masticatory joint is doubly 

 concave-convex (Afouotrcwata). 



VII. The quadrate is converted into the principal part of the 

 tympanic frame, viz. annulus tympanicus. The mandible has 

 lost its articulation with the quadrate, and the masticatory joint 

 is a single concave-convex one, the convexity belonging to the 

 mandible (Monodelphia). 



Edinburgh. 



Royal Society, April 2.— Rev. Prof. Flint, Vice-President, 

 in the chair.— Prof. Crum Brown communicated a paper by Dr. 

 Prafulla Chandra Ray on the conjugated sulphates of the 

 copper-magnesium group. — Dr. John Murray read a paper by 

 Mr. A. Dickie on the chemical analysis of water from the Clyde 

 area. — Sir W. Turner read a paper by Prof. His on the 

 principles of animal morphology. — Prof. Tait communicated 

 two mathematical notes. 



April 16. — Prof. Chrystal, Vice-President, in the chair. — Dr. 

 Buchan gave an analysis of the Chalkng r meteorological 

 observations, pointing out various important meteorological 

 conditions the existence of which had been revealed by the 

 work of the Challenger Expedition. — Dr. John Murray read a 

 description of the rocks of the Island of Malta, comparing them 

 with deep-sea deposits. — Prof. Chrystal described an electrical 

 method of reversing deep-sea thermometers. — Dr. Thomas 

 Muir read a paper on a class of alternants expressible in terms- 

 of simple alternants. — Prof. Tait communicated a quaternion 

 note. 



Paris. 



Academy of Sciences, April 30. — M. Jans-en, President, 

 in the chair. — On the consequences of the equality assumed to 

 exist between the true and the mean value of a polynome, by M. 

 J. Bertrand. The author shows by a rigorous demonstration 

 that the rule is not justified which gives a posteriori the precise 

 value of a system of observations, although this rule is frequently 

 applied with complete confidence in its accuracy. — On the 

 theory of the figure of the earth, by M. Maurice Levy. The 

 point here mainly discussed is the difficulty of establishing a 

 satisfactory agreement between the theory of fluidity and that of 

 precession in connection with Clairaut's differential equation and 

 the subsequent researches of Lipschitz inserted in vol. lxii. of the 

 Journal de Crelte. — Remarks in connection with Pere Dechev- 

 rens' recent note on the ascending movement of the air in 

 cyclones, by M. H. Faye. In order to solve by direct observa- 

 tion the question of the ascending or descending movement of 

 the atmosphere in cyclones, Pere Dechevrens has devised a 

 special anemometer for his observatory of Zi-Ka-\Vei in China. 

 But he suggests that more trustworthy results might perhaps be 

 obtained by fitting up a similar apparatus at a greater elevation 

 from the ground ; for instance, on the top of Eiffel's Tower, 300 

 metres high, now being erected in Paris. M. Faye accepts this 

 suggestion, confident that, if carried out, it cannot fail to confirm 

 his own views on the movement of the atmospheric currents in 

 cyclones. — An elementary proof of Dirichlet's theorem on 

 arithmetical progressions in cases where the ratio is 8 or 12, by 

 Prof. Sylvester. In this demonstration the author slarts from 

 the following principle : To show that the number of prime 

 numbers of a given form is infinite, let an infinite progression be 

 constructed of integers relatively prime to each other, and each 

 containing a prime number at least of the given form. — Distribu- 

 tion in latitude of the solar phenomena recorded during the year 

 1887, by M. P. Tacchini. A table is given of the spots, 

 eruptions, faculae, protuberances, as observed in each zone of io° 

 in the two solar hemispheres. The hydrogenic protuberances 

 occur in all the zones, whereas the other phenomena were 

 almost entirely restricted to the central region between o° and 

 ± 40°, as in the previous year. The spots, faculae, and metallic 

 eruptions present an agreement in the respective zones of maxi- 

 mum frequency between o° and ± 20 ; a maximum for each of 

 the three orders of phenomena corresponds to the zone o°-lo c 

 exactly as in 1886. The spots were confined to the equatorial 

 zone ( + 3O°-2O ) ; the eruptions and the faculae occurred at 

 much higher latitudes, in fact as far as +50 and -6o°. Hence 

 there are zones with faculce and eruptions, but without spots, 

 while on a great part of the solar surface hydrogenic protuber- 

 ances are observed in the total absence of spots. — In a second 

 communication, M. Tacchini gives a summary of the solar 

 observations made at Rome during the first quarter of the year 



