September 22, 1923] 



NA TURE 



455 



Research Items. 



The Horse in Babylonia. — In the June issue of 

 the Philadelphia Museum Journal Mr. Leon Legrain 

 describes a series of Babylonian seals in the museum 

 collection. In one of the most remarkable the rider, 

 whip in hand, is represented with a bird-like head in 

 profile with no distinct hair or beard, mounted on an 

 animal which may be a horse or a donkey. Mr. 

 Legrain is half disposed to regard this as the first 

 representation of the horse in Babylonia, but this is 

 far from certain. In the only known example of this 

 type the animal has been called a bull, and the rider 

 identified with the thunder god, Ramman Adad. But 

 as the seal probably dates from the time of the Guti 

 invasion, this mode of riding astride may be a new 

 and foreign feature imported from the north-east by 

 the Guti people. 



Effect of Drying upon the Skull. — In an in- 

 teresting paper in the Journal of Anatomy (vol. Ivii., 

 pt.iv., July 1923), T. WingateTodd discusses the effect 

 of maceration and drying upon the linear dimensions of 

 the green human skull. His observations cover the 

 effects of drying upon twenty-four macerated skulls and 

 the differences between eight green skulls and the same 

 within twelve hours of emergence from the macerator. 

 He concludes that great individual variation occurs in 

 percentage shrinkage, which, relatively small for 

 length, increases somewhat for breadth and height, 

 upon transformation from the green to the dry 

 macerated state. The average shrinkage (all dimen- 

 sions) amounts to about i-i per cent, of the final 

 measurement. The duration of measurable shrinkage 

 is about three weeks ; but shrinkage demonstrable 

 by shifting of the Euryon may continue for three 

 months. Sex, stock, age, cranial thickness, cranial 

 shape, and the condition of sutures are all eliminated 

 as factors having no influence upon shrinkage. In 

 passing through the stage of maceration, and during 

 the first few hours of drying, the green skull loses a 

 total average of 0-84 mm. in length, breadth, and 

 auricular height. The average total shrinkage in 

 complete transformation from the green to the dry 

 macerated state is given as 5-6 mm., corresponding 

 to a reduction of about 42 c.c. in a cranium of some 

 1500 c.c. capacity. The writer further gives examples 

 showing that, given the linear dimensions in green and 

 dry macerated states, it is possible to calculate the 

 shrinkage in capacity to within a few cubic centi- 

 metres by either the Cleveland formula or those of 

 Lee and Pearson. 



Bird Censuses in the United States. — The 

 United States Department of Agriculture has just 

 published, as Bulletin No. 1165, a " Report on Bird 

 Censuses in the United States : igi6 to 1920," by 

 May Thatcher Cooke, of the Bureau of Biological 

 Survey. The paper deals with an interesting attempt 

 to establish a statistical basis for the study of the 

 problems of bird population — the numbers and dis- 

 tribution of birds of different species, annual and 

 other fluctuations, and the effects of irrigation, of 

 cultivation, of the clearing of woodlands, and of 

 protective legislation. The subject is one both of 

 scientific interest and of economic importance : the 

 study of it is not unknown in Great Britain, but it 

 has not so far been undertaken on an important 

 scale. A census takes the form of an annual count 

 of the number of breeding pairs on a defined tract 

 of land which is taken to be representative of the 

 district as a whole. The conclusions so far reached 

 in America, as mentioned in the paper under notice, 



NO. 2812, VOL. I 12] 



are purely tentative, and only a part of the United 

 States is adequately covered by the records for the 

 period. For the section of the country lying north 

 of Maryland and the Ohio River and east of the Great 

 Plains, a little more than one pair of birds to the 

 acre is found to be the present average for farm land. 

 For the land immediately surrounding the farm 

 buildings, and including lawns and orchard, the 

 average is about 130 pairs per 100 acres, the estimated 

 population of an entire farm of 100 acres being about 

 112 pairs. The American robin {Turdus migratorius) 

 is the most abundant species in those States lying 

 north of North Carolina and east of the Mississippi, 

 and the alien house-sparrow {Passer domesticus) takes 

 second place : for farm land in this section there 

 are about 9 pairs of robins and 8 pairs of sparrows 

 per 100 acres. Further and more comprehensive 

 figures should make interesting comparisons possible. 



The Opalinid Ciliate Infusorians. — Dr. M. M. 

 Metcalf has recently published (U.S. Nat. Mus., 

 Bull. 120) what he describes as a preliminary review 

 — a memoir of 484 pp., with 258 illustrations — of 

 these ciliates which live in the rudimentary caecal 

 portion of the rectum of Anurid amphibia. Most of 

 the material used in the study of the 150 new species, 

 sub-species, and formae was obtained from museum 

 specimens of Anura which had lain long — some for 

 more than eighty years — in alcohol. The author gives 

 a general account of the structure and life-history of 

 Protoopalina intestinalis — a binucleate opalinid — -and 

 deals in some detail with mitosis and other nuclear 

 phenomena in this and other forms. He concludes 

 that each ordinary nucleus of an opalinid contains 

 both trophic and reproductive chromatin in full 

 activity. Dr. Metcalf discusses the relationships (a) 

 of the four genera — Protoopalina, Zelleriella, Cepedea, 

 and Opalina, and (6) of the family. He suggests that 

 the Opalinidae and Trichonympha may have arisen 

 from similar ancestors, and that still more probably 

 the Euciliata arose from ancestors which had become 

 disturbed in their relations of mitosis and fission, and 

 that they had passed through a pseudobinucleate 

 condition to one of true binucleation, finally reaching 

 their present structure, having two nuclei — one 

 hypertrophied for metabolism, the other inactive 

 except during the sexual period. An important 

 section of the memoir deals with the geographical 

 distribution of the species of Opalinidae and the 

 families and sub-families of the Anura. 



Skin Spot of Potatoes. — Skin spot has frequently 

 been regarded as a relatively unimportant blemish 

 upon the potato tuber, so that considerable interest 

 was aroused by the recent announcement by 

 Shapovalov (Journ. of Agricultural Research, vol. 23, 

 pp. 285-294) that the pustules of this disease repre- 

 sent a primary stage of corky scab, a much more 

 serious trouble produced by Spongospora subterranea. 

 Until this paper, it had been generally assumed on 

 the basis of a paper by Miss M. N. Owen {Kew 

 Bulletin, 1919, pp. 289-301) that skin spot was due 

 to quite a different organism, a new species of Oospora, 

 named by the discoverer O. pustulans Owen and 

 Wakef. As skin spot frequently occurs upon seed 

 tubers of many of the best-known varieties of potatoes, 

 it was obviously of great importance to know whether 

 the organism causing skin spot could also give rise to 

 corky scab, and potato-growers will read with relief 

 the communication by W. A. Millard and Sydney 

 Burr in Kew Bulletin, No. 8 for 1923. This Work 



