January 12, 1911] 



NATURE 



145 



pointe a main " of Mortillet. Falls of rubble have now 

 ndered it impossible to make further examination of this 

 ::e at present. 



In the Johns Hopkins Hospital Bulletin for December, 

 iio, there is an instructive article by Dr. Lewellys F. 



barker on electrocardiography and phonocardiography, and 

 >iitaining many illustrations of the apparatus employed 

 id of the cardiograms obtained. It is chiefly remarkable 

 r the description of the electrocardiographic installation 

 the medical clinic of the Johns Hopkins Hospital, which 

 ows that the apparatus may be fitted up at a smaller 

 ist than is generally supposed, and that it may be applied 

 1 the diagnosis of a good many cardiac and nervous 



; seases. The remarkable progress in this department of 

 ::nical inquin*- is well shown in this paper, and especially 

 , the analysis of the many curious cardiograms obtained 

 : Baltimore and elsewhere. 



In the Proceedings of the Royal Society, ser. B, vol. 



Ixxxiii., p. 124, Dr. R. Kirkpatrick describes, under the 



name of yiurrayona phanolepis, a new type of sponge from 



Christmas Island, Indian Ocean, referable to the family 



ommonly known as the Pharetronidae, equivalent to the 



haretrones of Zittel. When this group was first estab- 



-hed, it was believed to be extinct, with its latest repre- 



ntative in the Maestricht Chalk, but, inclusive of the 



•^w Christmas Island form, which constitutes a subfamily 



y itself, six living genera, each with a single species, are 



ow known. Murrayona differs from all the other genera 



1 that the skeleton consists of a firm basal network 



void of spicules, overlain by a dermal layer of scales, 



le axial core of spicules found in the other living genera 



aving been discarded. The absence of spicules in some 



f the fossil Pharetrones may be due to the same cause, 



'though in other instances (as has hitherto been con- 



dered to be the case with all) it may be the result of 



fossilisation. Apparently there is no such genus as 



Phareton, and if this be the case the family requires a 



ew name. 



The two articles in the Journal of Economic Biology for 



December, 1910, are devoted to "warbles." In the first 

 f these Prof. G. H. Carpenter furnishes notes on the 

 fe-history of the reindeer warble-fly (CEdemagena 

 irandi), his specimens being derived from a young rein- 

 ;?er in the Dublin Zoological Gardens. He finds that 

 he egg of CEdemagena has a thin flap at the free end, 

 I long the edge of which the egg-case readily splits. The 



position and appearance of this recall the " lid " of the 

 3g of the horse bot (Gastrophilus equi), and suggest that 

 he maggots of CEdemagena are licked off and swallowed 

 ■y the reindeer immediately after hatching. In Hypo- 

 erma iovis, the ox warble, the egg has no such lid, which 

 nds support to the suggestion that the host swallows the 



'?ggs instead of the maggots. In the second article Messrs. 



Cooper and Nuttall, who accept the idea that cattle lick 

 ff the eggs of Hypoderma from their legs as a definite 

 ict, discuss means of preventing the destruction of hides 

 y warbles. A hide was cut into four quarters, of which 

 iree were severally treated with different chemicals, 

 ncluding picric acid, and it was found that in none of 

 he cases was tanning interfered with. It is recommended 

 hat the experiment of treating the legs of oxen with picric 

 :id should be tried. 



The current number of the Quarterly Journal of Micro- 



copical Science (December, 1910) contains an elaborate 



md very interesting memoir, by Prof. J. P. Hill, on the 



arly development of the Marsupialia, with special refer- 



-rnce to the native cat (Dasyurus viverrinus). This forms 



NO. 2150, VOL. 85] 



the fourth of the author's well-known contributions to the 

 embryolc^y of the marsupials, and in it he describes in 

 detail the process of cleavage, the formation of the blasto- 

 cyst, and the differentiation of the embryonal ectoderm 

 and endoderm. The uterine ovum possesses a shell- 

 membrane and a layer of albumen outside the zona, 

 analogous with the corresponding structures in the egg of 

 monotremes, but is much smaller than the latter, and 

 contains much less yolk, its condition in these respects 

 being intermediate between that of the monotreme and 

 that of the eutherian egg. The character of its early 

 development is also intermediate between that of the two 

 latter groups. Cleavage is complete, and at first 

 meridional, resulting in the formation of a ring of eight 

 blastomeres placed equatorially within the egg-shell, 

 followed by an equatorial cleavage which divides each 

 blastomere into two, an upper, smaller, and clearer, and 

 a lower, larger, and more opaque. Two rings, each of 

 eight cells, are thus formed, the upper one giving rise to 

 the embryonal region of the blastocyst wall, and the 

 lower to the extra-embryonal r^ion, which the author 

 regards as homologous with the trc^hoblast of the 

 eutherian ovum. Prior to the completion of the first 

 cleavage, the egg eliminates from itself a spherical mass 

 of yolk which takes no direct part in development, though 

 it becomes enclosed in the blastocyst cavity. The paper 

 includes a valuable discussion of the early ontogeny of the 

 Mammalia, in which the author defends the generally 

 accepted view that the mammals are descended from 

 ancestors which had large, heavily yolked eggs, and 

 vigorously opposes the recently promulgated theor>- of 

 Hubrecht, in accordance with which the alecithal 

 character of the eggs of higher mammals represents the 

 primitive condition. He also entirely disagrees with 

 Hubrecht 's interpretation of the trophoblast as an 

 embryonic membrane comparable with that of the nemer- 

 tines and other invertebrates. The " entjpic " condition 

 of the eutherian embr}"0 is explained as a secondary 

 modification due to*the loss of the egg-shell. 



A NOTE by Miss A. G. St<Jcey on the sporangium of 

 Lycopodium pithyoides, published in the Botanical Gazette 

 (September, 1910), indicates that the sporangium arises 

 from the leaf, but during development grows away from 

 it, and appears to be cauline. In size and shape, as well 

 as in the proportion of wall cells, the sporangium 

 resembles that of L. dichotomum. 



The annual report, for 19 10, of the Department of Agri- 

 culture, Trinidad, by Prof. P. Carmody, covers the reports 

 of the botanical departments in Trinidad and Tobago, of 

 various estates, and the Government laboratories. The 

 cacao exports for the year were the highest on record; 

 crops of sugar-cane were good, but the sucrose content of 

 the Juice proved to be small. Analyses of Castilloa rubber 

 trees of different ages showed that the latex in young trees 

 contained more than 50 per cent, of resin, and this de- 

 creases to about 8 per cent, after eight or ten years. 



A CYTOLOGICAL investigation of corn rust, Puccinia 

 graminis, described by Dr. F. Zach in the Sitzungsberichte 

 der Kaiserlichen Akademie der Wissenschaften, Vienna 

 (.^pril, 1910), deals with the crucial stage when the fungus 

 invades the palisade cells of the leaf and enters upon a 

 contest with the protoplasm and nucleus. Sometimes the 

 fungus is worsted and its hyphae are dissolved ; in other 

 cases the fungus is victorious, when the protoplasm and 

 nucleus are disintegrated and certain portions are excreted. 

 It is suggested that the power of the host to withstand 

 the attack of the parasite is partly innate, but to a great 



