52^ 



NA rURE 



[March 29, 1894 



and as such might be expected to throw light upon the trilobites. 

 Since the publication of this work he had been studying the organi- 

 sation of the trilobites themselves, and the results were given in 

 the present communication. He discussed the great variability 

 in thenumber of segments shown by the trilobites ; the formation 

 of the head by the gradual incorporation of trunk-segments ; 

 t! e bending round ventrally of the first segment ; the " wander- 

 ing " of the eyes ; the existence and modification of the " dorsal 

 organ " ; and especially the character of the limbs. As a 

 result of this discussion, he stated that the zoological position of 

 the trilobites can now be fixed with considerable probability. 

 The features described serve to connect the trilobites with 

 ApKs. Aptis must be assumed to lie low in the direct line up 

 from the original annelidan ancestor towards the modern Crus- 

 tacea, and the trilobites must have branched off laterally from 

 this line, either once or more than once, in limes anterior to the 

 primitive Apus, as forms specialised for creeping under the 

 protection of a hard imbricated carapace, obtained by the repe- 

 tiiion on every segment of the pleuraa of the head-segments, 

 which together form the head-shield. The trilobites may be 

 briefly described as fixed specialised stages in the evolution of 

 the Crustacea from an annelidan ancestor with its mouth bent 

 round ventrally, so as to use its parapodia as jaws. The Presi- 

 dent agreed with Mr. Bernard that the earlier trilobites pre- 

 sented forms with very numerous segments, but pointed out that 

 the later ones showed signs of advance in having fewer free 

 thoracic rings and a well-developed pygidial shield. He had 

 always cherished the idea that the Isopoda might have branched 

 off at some distant time from the Trilobita, and he drew atten- 

 tion to such points of structure as the pores in the free cheeks, 

 which were present in such isopods as Sphuroma and Scolis, 

 and in such trilobites as Phillipsia, Gritjithidcs, Ampyx, and 

 Trimicleiis. The Rev. T. K. Stebbing agreed with the author 

 in thnking that the trilobites have little connection with the 

 isopods, though tlieresemblancewas sometimes striking, and was 

 often favoured rather than otherwise by the character and posi- 

 tion of the eyes. Prof G. B. Howes said that he believed the 

 discovery of the terminal anus in the trilobite dealt the death- 

 blow to the association of the trilobites with the arachnoid 

 series. He believed that the facts and arguments brought for- 

 ward by the author of the paper proved the trilobites to be 

 Crustacea, and fully justified their association with Apiis as an 

 early offshoot on the crustacean line. Mr. Malcolm Laurie also 

 spoke, and the author replied. — Landscape marble, by Mr. 

 Beeby Thompson The Coiham stone is a hard, close-grained, 

 argillaceous limestone with conchoidal fracture. The dark 

 arborescent markings of the stone rise from a more or less stra- 

 tified dark base, spread out as they rise, and terminate upwards 

 in wavy banded portions of the limestones. In some specimens 

 two "landscapes " are seen, one above the other, each rising 

 from a distinct dark layer. The author described the micro- 

 scopical and chemical characters of the rock, and its mode of 

 occurrence, and discussed the explanations which have been put 

 forward to account for its formation, especially that of Edward 

 Owen, who in 1754 gave the first [mhlished description of the 

 Cotham stone, and that advancedby Mr. H. B. Woodward in the 

 Geological 3fagazi7ie for 1892. He then proposed a new expla- 

 nation to account for the formation of the rock, and maintained 

 that its peculiar characters are due to interbedded layers of 

 vegetable matter, which decomposed and evolved carbonic acid 

 gas and marsh gas. This deuomposition continued while several 

 inches of new sediment were laid down, the result being that 

 arborescent markings were produced along the Imes taken by 

 the escaping bubbles, and that the upward pressure of these 

 gases, after their escape had been prevented by increasing 

 coherence or greater thickness of the upper layers of sediment, 

 caused the corrugations in the upper surface of the stone. He 

 further discussed the composition of the stone, and described 

 expt-riments which he made to illustrate his views. Mr. H B. 

 Woodward, Prof. T. Rupert Jones, Mr. F. A. Bather, and Mr. 

 M()nck;on spoke upon the subject of the paper, and the author 

 replied. — On the discovery of molluscs in the Upper Keuper at 

 Shrewley, in Warwickshire, by the Rev. P. B. Brodie. Mr. 

 R B. Newton read a paper at the meeting of the Bruish Asso- 

 ciatum at Nottingham in 1893, on some lamellibranchs found 

 at Shrewley by the author of the present paper and Mr. 

 Richards. This paper gave details of the section where the 

 shells were found, and their interest and importance were pointed 

 out, no shells having been previously detected anywhere in the 

 New Red Sands one in this country. 



NO. 1.274, VOL. 49] 



Entomological Society, March 14. — Colonel Swinhoe, 

 Vice-President, in the chair. — Dr. D. Sharp, F.R.S., exhibited 

 a collection of white ants {Termites), formed by Mr. G. D. 

 Haviland in Singapore, which comprised about twelve species, 

 of most of which the various forms were obtained. He said 

 that Prof. Grassi had recently made observations on the 

 European species, and had brought to light some important 

 particulars; and also that in the discussion that had recently been 

 carried on between Mr. Herbert Spencer and Prof. Weismann, 

 the former had stated that in his opinion the different forms of 

 social insects were produced by nutriiion. Prof. Grassi's ob- 

 servations showed this view to be correct, and the specimens 

 now exhibited confirmed one of the most important points in 

 his observations. Dr. Sharp also stated that Mr. Haviland 

 found in one nest eleven neoteinic queens — that is to say, 

 individuals having the appearance of the queen in some respects, 

 while in others they are still immature. Mr. Haviland gave an 

 account of the structure of some of the nests, and staled that two 

 of the species of white ants exhibited certainly grow fungus for 

 their use, as described by Smeathman, many years ago, in the 

 Philosophical Transactions. Mr. H. Goss remarked that the 

 fact that the different forms of social insects were produced by 

 nutrition was known to Virgil, who referred to it, and to the 

 subject of parthenogenesis in bees, in the " Georgics," book iv. 

 Mr. McLachlan, Colonel Swinhoe, Mr. Champion, Mr. Jenner- 

 Weir, and Dr. Sharp continued the discussion. — Mr. O. E. 

 Janson exhibited specimens oi Dicranocephalia adatnsi, Pascoe, 

 from Sze-chuen, VVestern China, and D. dabryi, Auz., recently 

 received from the neighbourhood of Moupin, in the same 

 district ; he observed that, although the latter had been quoted 

 by Lucas, liates, and others, as a synonym oi adamsi, the two 

 species were perfectly distinct; the females of both were unknown 

 to the authors when describing them, and presented a remarkable 

 difference. — Mr. C. O. Waierhouse exhibited, for Mr. E. A. 

 Waterhouse, a specimen of Colias edusa resemblmg C. 

 erate, a continental species, which was taken on Wimble- 

 don C>mmon ; a varied series of Chrysophanus phlceas, 

 from Barnes Common ; and a series of Lycccna arion, from 

 Cornwall. — The Rev. Canon Fowler read a paper entitled 

 "Some ^ev/ Sp^diesoi Afemhracidce." — Mr. F. Merrifield reada 

 paper entitled "Temperature Experiments in 1893, on several 

 Species of Vanessa and other Lepidoptera!" He said that the 

 results tended to confirm Dr. Dixey's conclusions as to the origin 

 of the wing-markings in the Nynphalida;, brought out many 

 ancestral features, and in some cases were very striking. There 

 was much difference in sensitiveness between the seasonal 

 broods of the same species, even in V. c-all)tcm, although both 

 broods of that species passed the pupal state in the wa' mrr part of 

 the year.— Dr. Dixey read a paper entitled " On Mr. Mernfield's 

 Experiments in Temperature- variation as bearing on Theories of 

 Heredity," which was supplemental to the previous paper. 

 Colonel Swinhoe, Mr. Hamps >n, Mr. Jenner-Weir, Mr. 

 Merritield, and Dr. Dixey took part in the discussion which 

 ensued. 



Linnean Society, March 15. — Prof. Stewart, President, in 

 the chair. — Mr. Clement Reid exhibited some cones of Scotch 

 fir, and also some carbonised pine wo<id from a peat moss at 

 Parkstone, Dorset. He said the pine had become extinct in the 

 South of England after Neolithic times, and had been reintro- 

 duced only recently. Its extinction was commonly supposed to 

 be due to forest fires. He foutid that every piece of pine wood 

 imbedded in the t>eat moss was similarly chaired, while portions 

 imbedded in sand were little altered, and he -uggesied that the 

 appearance of burning might possibly be due to the action of 

 the growing peat, and have nothing to do with fire. A dis- 

 cussion followed, in which Messrs Carruthers, Hanbury, Christy, 

 and others gave reasons for adhering to the older theory. Mr. 

 Carruthers exhibited a diagrammatic table showing an accurate 

 counting of the annual rings ol growth in three gigantic specimens 

 of Wellingtonia, Sequoia giganiea, from whicli he calculated the 

 age of the trees (see p. 507). A section of one in ihe British 

 Museum (Natural History), fifteen feet in diameter, which wasa 

 living tree when cut down, he estimated to be 1330 years old. 

 As illustrative of the size to which these trees giow, he mentioned 

 that he had measured two in America, one of which was 92 

 feet and the other 77 feet in circumference. A discussion 

 followed on the conditions which acceleraied or reiarded 

 growth, and Mr. G. Murray, in reply to a suggestion of 

 Mr. Reid, pointed out that a number of experiments had 



