April, 28, 1887] 



NA TURE 



623 



c.iched here (probably in the extreme case less than 3) with 

 he value 20,000, which was found by one of the authors in the 

 i>e of a soft wire exposed to a very small magnetising force 

 rid kept at the same time in a state of mechanical vibration. 



The experiments give n.i support to the suggestion that there 

 :s a maximum of the induction, 13. The value of U capable of 

 lieing reached by tlie method here employed depends mainly 

 m the scale of tlie experiments. Larger field magnets with 

 pole-pieces t.apering to a narrow neck should yield values of C 

 j^reatly in excess even of those that were observed. 



I Linnean Society, .\pril 7. — Mr. William Carruthers, F.R.S., 



I President, in the chair. — Mr. Hunter J. Barron, Mr. Jas. H. 

 r Dugdale, and Mr. Edwd. B. Poulton were elected Fellows of 

 the Society. — Fresh specimens were exhibited of a pure white 

 variety of primrose, which had been gathered, growing wild, 

 near Biarritz, France, by Mr. W. D. Godolphin Osborne.— A 

 large series of instantaneous photographs of storks nesting, &c., 

 were exhibited for Mr. E. Bidwell. These had been taken in 

 Germany, and were specially interesting as showing the peculiar 

 attitudes assumed in flight, &c. — Some malformed trout in an 

 early stage of development were shown and commented on by Dr. 

 F. Day. — A paper was read by Prof. Huxley on " The Gentians ; 

 Notes and Queries." Taking the flower as a basis, he divides 

 the Gentianea: into two great series, each of which is character- 

 ised by a peculiar disposition of the nectarial organs, and a 

 gradation of forms of the corolla from the deeply cleft rotate 

 or stellate condition, through the campanulate to the extreme 

 infundibulate kind. In one series termed (I.) Perimelitrc, the 

 nectarial cells are aggregated in a single or two patches ; in the 

 other series (II.) Mesomelit:e, the distinguishing characters are 

 a zone of secreting cells encircling the ovary, or absence of such, 

 with presence of a honey-secreting surface which may exist in the 

 central parts of tlie flower. He assumes, on morphological 

 grounds, a hypothetical ancestral flower or Ur-Gentian = Hap- 

 lanthe. As a starting-point, this would lead, on the one hand, 

 to the series of Perimelitaa;, with four subsidiary types ; and on 

 the other to the Mesomelitse, also with four subsidiaiy types 

 of floral structure. The Perimelita: comprise the groups: — 

 I. Actinanthe, 2. Keratanthe, 3. Lophanthe, and 4. Stephananthe ; 

 the MesomelitLie comprise: — I. Asteranthe, 2. Limnanthe, 

 3. Lissanthe, and 4. Ptychanthe. The one series appears to 

 bear a certain progressive relation in its evolution to the leading 

 morphological modifications of the opposite series. In treating 

 of the geographical distribution of the gentians, Prof. Huxley 

 adopts the lines previously followed by him on animal distribu- 

 tion. Under (I.) Arctogea he includes Europe, Africa, Asia, 

 and North America as far .is Mexico ; South Africa, Madagas- 

 car, Hindostan, and Indo-China foraiing a sub-province = South 

 Arctogea; the remainder = Nortli Arctogea. (II.) Austro- 

 Columbia comprises .South America, isthmus and islands as far 

 north as Mexico. (III.) .\ustralia is another province; and 

 (IV.) New Zealand with adjoining islands. Species of the 

 Gentianex are found in all these provinces, the head-quarters 

 being North Arctogea and .Austro-Columbia. The Ptychanthe 

 are predominant in North Arctogea ; the Lissanthe in South 

 Arctogea ; and Actinanthe, Lophanthe, and Lissanthe in Austro- 

 ' -olumbia. In Australia and New Zealand there is a paucity of 

 -pecies. He considers that the present distribution of the 

 Gentianese is not to be accounted for by migration from any 

 given centre, whence difi'usion to their present localities. Bor- 

 rowing analogy from zoological distribution, he likens the 

 gentians to the tapirs, at present only represented in South 

 America and the Indo-Malayan region. Yet the Tapiridse in 

 the Middle Tertiary epoch were distributed everywhere in the 

 intermediate areas. Though fossil remains of gentians are not 

 yet known. Prof. Huxley nevertheless suggests that in Pliocene 

 and Miocene times their distribution may have been sub aantially 

 similar to what is now extant. He further throws out the hint 

 that, could the age of the first appearance of dipterous, 

 hymenopterous, and lepidopterous insects provided with long 

 haustra be indicated, we should then be in a position to guess 

 approximately when specialisation of the types of the gentians 

 and their ultimate distribution occurred. 



Geological Society, April 6.— Prof. J. W. Judd, F.R S., 

 President, in the chair. — The following communications were 

 read : — On the rocks of the Malvern Hills, part 2. by Mr. 

 Frank Rutley. The details of the microscopic examination of 

 the rocks constituted the principal part of the present paper. 

 The author concluded that the rocks of the Malvern Hills 



represent part of an old district consisting of plutonic and, 

 possibly, of volcanic rocks associated with tuffs, sedimentary 

 rocks composed mainly or wholly of eruptive materials, and 

 grits and sandstones ; that the structural planes in these rocks 

 (sometimes certainly, at others possibly) indicate planes of strati- 

 fication, and that the foliation, in many cases if not in all, 

 denotes lamination due to deposition either in w-ater or on land 

 surfaces, probably more or les< accentuated or altered by the 

 movements which produced the upheavals, subsidences, and 

 flexures prevalent in the range. — On the alleged conversion of 

 crystalline schists into igneous rocks in County Galway, by Dr. 

 C. Callaway. — A preliminary inquiry into the genesis of the 

 crystalline schists of the Malvern Hills, by Dr. C. Callaway. 

 The author's researches amongst the crystalline rocks of Con- 

 naught had suggested certain lines of investigation which had 

 subsequently been followed out in the Malvern district. He h.id 

 satisfied himself that many of the Malvern schists had been 

 formed out of igneous rocks ; but at present he limited himself 

 to certain varieties. The materials from which these schists were 

 produced were diorite (several varieties), granite, and felsite. 

 The metamorphism had been brought about by lateral pressure. 

 Evidence of this was seen in the intense contortion of granite- 

 veins and in the effects of crushing as observed under the 

 microscope. The products of the metamorphism were divided 

 into two groups : — (l) Simple schists, or those formed from one 

 kind of rock. (2) Injection schists, formed by the intrusion of 

 veins, which had acquired parallelism by pressure. Veins of 

 diorite in diorite produced duplex diorite-gndss, and veins of 

 granite in diorite originated granite diji-ile-gitdu. It was 

 further noted that (i) generally the particular v.arieties of schist 

 occurred in the vicinity of the igneous masses to which they 

 were most nearly related in mineral composition ; (2) the 

 mineral banding of the rocks in the field was inore like vein- 

 structure th.an stratification. The author accepted the received 

 view of the age of the schists. The parallel structure was 

 clearly antecedent to the Cambrian epoch, and the occurrence of 

 similar rocks as fragments in the Uriconian conglomerate of 

 Shropshire seemed to indicate that ihe Malvernian schists were 

 older Archfean. The- reading of this paper was followed by a 

 discussion in which the President, Mr. Teall, Dr. Hicks, Colonel 

 McMahon, Dr. Callaway, and Mr., Rutley took part. 



Entomological Society, April 6.— Dr. David Sharp, 

 President, in the chair. — Mr. Francis Gallon, F. R.S., Mr. J. 

 H. Leech, B.A., F.L.S., and Mr. G. S. Parkinson, were 

 elected Fellows. — Mr. S. Stevens exhibited specimens of Arctia 

 meitdica, collected in the county of Cork. The peculiarity of 

 the Cork form of the species is that the majority of the males are 

 as white as the female of the English form, and the typical black 

 or English form appears to be unknown in Cork. — Mr. 

 McLachlan exhibited a zinc box used by anglers for the purpose 

 of keeping living flies in, which he tho.ight might be adapted to 

 practical use in the field by entomologists. — Mr. G. T. Porritt 

 exhibited specimens oi Hybernia progemmiria, from Hudders- 

 field. All the females and a large proportion of the males were 

 of the dark variety /'«j<ra/a, which formerly was .almost unknown 

 in Yorkshire, but which now seemed likely to replace the original 

 type.. Mr. Jenner-Weir and Lord Waisiagham both remarked 

 that the number of melanic forais appeared to be on the increase 

 in the north, and suggested explanations of the probable causes 

 of such increase. — Mr. Gervase F. Mathew, R. N., exhibited 

 several new species of Rhopalocera taken by him in the Solomon 

 Islands during the visits to those islands of H.M.S. Espiigle 

 in 1882 and 18S3. Amongst them were species of Euplcca, 

 Mycalesis, Mcssariis, Rhinop dpa, CyresHs, Diadcina, Parthenos, 

 Pieris, Papilb, &c. — Mr. E. B. Poulton exhibited a large 

 and hairy lepidopterous larva brought from Celebes by Dr. 

 Hickson, and made remarks on the urticating properties of 

 the hairs of the species, which were said by the natives to 

 produce symptoms similar to those of erysipelas if the larva was 

 handled. Lord WaUingham, Mr. McLachlan, Dr. F. A. 

 Dixey, Mr. Jenner-Weir, Dr. Sharp, Mr. Slater, and Mr. 

 Poulton, took part in a discussion as to whether urtication 

 was due to the mechanical action of the hairs in the skin, 

 or to the presence ,of fonnic acid, or some other irritant 

 poison, in glands at the base of the hairs. There appeared to 

 be no doubt that in some species the irritation caused by 

 handling them was merely due to the mechanical action of the 

 hairs. — Mr. P. Crowley exhibited a collection of Lepidoptera 

 recently received from West Africa, including several new or 

 undescribed species of Afy/otkris, Diadema, Ijariiia, Khomaleo- 



