474 



NATURE 



[September 8, 1904 



As the result of anatomical investigations in butterflies, 

 Mr. Petersen, of Reval, attempted to show that all species 

 can be distinguished morphologically by their reproductive 

 organs, and that it is through physiological isolation that 

 varieties form the starting point for new species. 



Prof. Maas reviewed the experiments he had carried out 

 in depriving young sponges of carbonate of lime before their 

 metamorphosis. 



Prof. Vejdovski demonstrated the presence of a nucleus 

 in Bacterium Gammari, already described (c/. Centralblatt 

 f. Bakteriologie, iqoi and 1904), while Prof. Looss, of 

 Cairo, indicated how the larvae of Ancylostomum and 

 Strongyloides migrate through the hair-follicles of the 

 human hand into lymph- or blood-vessels, and from there 

 reach the intestine by Tvay of the heart, lungs, and air 

 passages. 



II. — Vertebrata (Systematic). 



Several papers of particular interest were discussed in 

 this section. Among these may be mentioned that of Prof. 

 Scott, of Princeton, on the Miocene mammals of Patagonia. 

 He referred to the fact that the fossil rodents all belong 

 to the Histricomorpha, of which South America is still the 

 headquarters. The Edentata are represented by the three 

 orders Gravigrada, Dasypoda, and Glyptodontia. Several 

 orders of ungulates, he remarked, displayed striking 

 similarities to northern orders, but these similarities must 

 be looked upon as convergent developments, and not due to 

 a common descent. 



Mr. Bieler, of Lausanne, described the skull of an 

 extremely small bear obtained in the Alps some years ago, 

 which he identified as belonging to Ursus formicarius. 



An artificially produced hybrid between Triton cristatus 

 and T. marmoratiis was exhibited by Dr. Wolterstorff , who 

 remarked on its identity with Triton Blasii. 



Mr. Borodine, of St. Petersburg, described the herrings 

 of the Caspian, in which sea he was able to distinguish no 

 less than five species, three of which were essentially marine 

 forms. 



Recent studies and discoveries in the evolution of the 

 horse, with lantern demonstrations, formed the subject of 

 an interesting lecture by Prof. Osborn, who mentioned that 

 more than a hundred more or less complete skeletons of 

 horses and horse-like animals had been found fossil in North 

 .America. He thought he had established the fact that 

 horses were polyphyletic, there being four or five con- 

 temporary series in the Miocene, but that the direct origin 

 of the genus Equus in North America was not established 

 with certainty. 



Prof, von M^hely's paper dealt with the skull and denti- 

 tion of the species of Spalax, a small East European rodent. 

 As the result of his careful investigations he was able not 

 only to demonstrate that the twelve species described 

 hitherto could be reduced to three, but that the origin of 

 the latter was clearly traceable from an extinct form by 

 gradual mutations, due chiefly to selection. 



Prof. Tornier dwelt on the subject of the origin and 

 significance of the coloration of the skin in reptiles, and 

 attempted to demonstrate that those parts which were folded 

 during the animals' movements were less well nourished 

 than the remaining parts, and were therefore lighter in 

 colour. 



III. — Vertebrata (Anatomy and Embryology). 



Dr. Kerbert referred to the fact that the giant salamanders 

 of Japan in the aquarium at Amsterdam had produced 

 young, and described the eggs of the species ; while Dr. 

 Bashford Dean, of New York, pointed out the peculiarities 

 in the development of Chimaera Collici. 



The specimens of Ceratodus brought back from Australia 

 by the Semon Expedition enabled Prof. Burckhardt, of Basle, 

 to undertake some anatomical investigation of its central 

 nervous system, of which the author exhibited illustrations 

 and models, and he also showed some reconstructions of 

 fossil vertebrates not hitherto figured. 



Prof, van Wijhe, of Groningen, gave a demonstration on 

 the development of the skull in elasmobranchs, while Prof. 

 Lonnberg, of Stockholm, exhibited a foetal Elephas cyclotis, 

 and made some remarks on the homologies of the avian 

 hill. 



Dr. Helbing, of Basle, communicated the results of his 

 NO. 18 19, VOL. 70] 



investigations on the anatomy of Laemargus, and Mr. Bles 

 spoke on the hatching of Anuran tadpoles and the function 

 of Kupfer's " Stirnknospe." He also exhibited Prof. 

 Kerr's slides of the early development of the motor nerve 

 trunks in Lepidosiren paradoxa. 



IV. — Invertebrata (exclusive 0/ Arlhropoda). 



Prof. Meyer, of Kasan, described the primitive ambulacral 

 system in Echinoderms, and the diaphragm-sacs which serve 

 to swell the head tentacles in terrebelloid annelids, and dis- 

 cussed the theoretical bearings resulting from a comparison 

 of these somewhat similar structures. 



Prof. Salensky gave an account of the prototroch, and also 

 referred to the formation of coelomesoblast of t-he larva of 

 Echiurus, while the morphology of the cardial organs of 

 Appendicularia formed the subject of another of his papers. 



A description of the mode of nutrition of the embryos of 

 Purpura was then given by Prof. Pelseneer. It appears that 

 the majority of the ova undergo an irregular segmentation 

 and form a vitelline mass, on which a few embryos fix them- 

 selves and absorb it completely. 



Profs. Caullery and Mesnil exhibited preparations of two 

 ccelomic annelid parasites. The first of these, Pelmato- 

 sphaera polycirri, forming numerous spheres, is allied to the 

 Orthonectida, and lives in the general body-cavity of the 

 host. The next, Sphaeractinomyxon Stolei, is the first 

 marine representative of the Actinomyxidse, and inhabits 

 marine Oligochaets. 



Prof. Fuhrmann, of Neuchatel, described the three known 

 species of Cestodes in which the sexes are in distinct in- 

 dividuals, and which are characterised by very marked 

 dimorphism. 



It was urged by Prof. Monticelli, of Naples, that the 

 Temnocephala, for which he proposes the name of Dactyloda, 

 should be looked upon as constituting a group distinct from 

 the Platelminthes. 



The most exciting exhibition in this section, and, indeed, 

 one of the most fascinating features of- the congress, was 

 a kinematograph demonstration of the development of one 

 of the Botryllidae. These were kept in a flat-sided glass 

 jar to which a constant stream of fresh sea- water was 

 supplied. Taking a series of photographs at certain regular 

 intervals by means of an ingeniously constructed registering 

 camera, Prof. Pizon, of Nantes, succeeded in producing 

 before the audience a continuous and rapid picture of the 

 gradual evolution of the colonies of the Tunicate. Prof. 

 Marey had shown us some years ago how the quick move- 

 ments of animals such as the horse and the dog could be 

 reduced on the screen to slow motions, while Prof. Pizon 

 now demonstrated how this can be accomplished in a con- 

 \'erse manner. 



V. — Arthropoda. ■ 

 Most of the papers in this section dealt with ants. Dr. 

 Forel brought forward some new biological observations, in 

 the course of which he mentioned that there were now about 

 4000 species known, and 900 varieties ; while Prof. Emery 

 discussed the origin of ants' nests ; Dr. v. Buttel-Reepen 

 the insect colonies in general ; Mr. Pi^ron the problem of 

 recognition among ants; and Prof. Goeldi, of Para, the 

 mushroom gardens constructed by .Atta cephalotes. 



A few other papers dealt with Lepidoptera, such as that 

 of the Countess v. Linden on the influence of the with- 

 drawal of oxygen during the pupal stage on the shape of 

 butterflies, and that of Mr. Pictet on variations produced 

 in butterflies by changing the food of their caterpillars and 

 by humidity. ■ ■ 



Two communications deserve a special reference, viz. Prof. ' 

 Blanc's discovery of a Caprellid in the Lake of Geneva, and 

 Prof. Heymons's paper on the development of the Solifuga. 

 Prof. Blanc exhibited a female specimen of an undescribed 

 Podalirius, a marine genus of crustacean, and mentioned 

 that other invertebrates allied to marine forms were known 

 to inhabit the lake. The development of the Solifuga 

 agrees, according to Prof. Heymons, in all important respects 

 with that of the Arachnida, but it offers no clue to any closer 

 relationship with insects, as some authors seem to think. 



V. — .\piJLiED Zoology. 



I Dr. Jentink's discourse on the ideal natural history 



museum was delivered in this section. The director of the 



