508 6. Vererbungslehre. 



entire leaves, while the „okra" varieties have deeply divided narrow leaves. 

 Crosses between varieties having simple and Compound leaves give an inter- 

 mediate uniform F 1( with Mendelian segregation in the F 2 . Thus the same 

 characters which show alternative Mendelian inheritance in cotton are equally 

 definitely contrasted in the internodes of the same plant in related genera. 

 The conclusion is drawn, that dimorphic differences, mutations and Mendelian 

 behaviour, which show abrupt changes, are to be considered as phenomena of 

 alternative expression rather than alternative transmission of characters, 

 since the same kinds of characters show dimorphic specialization in individual 

 plants and Mendelian segregation in hybrids. Gates (London). 



1676) Shearer, C, W. de Morgan and H. M. Fuchs (Cambridge Uni- 

 versity and Plymouth Biolog. Laboratory.), Preliminary ISotice on the 

 Experimentai Hybridization of Echinoids. 



(Journ. Marine Biol. Association 9,2. p. 121 — 141. 1911.) 

 The authors made crosses between Echinus acutus, E. esculentus 

 and E. miliaris, and have reared the hybrids to the young urchin stage. 

 The methods used are fully described. With regard to inheritance, it is con- 

 cluded that the young larvae are too variable to afford definite evidence of 

 parental influence, this being especially true in the case of the skeleton. In 

 general, although the maternal iufluence is stronger, the conclusions of Loeb, 

 King and Moore are confirmed, that certain skeletal characters one dominant, 

 irrespective of the parent from which they are derived. Although the skeleton 

 gives indecisive results, it is found that in the lates larva the posterior cilia- 

 ted epaulettes, green pigment masses, and posterior pedicellaria are definitely 

 heritable characters, in which the larvae always follow the female parent. 

 The hybrid urchins, now two years old, appear of maternal type. Hybridi- 

 zation probably occurs in nature between E. acutus and E. eculentus. 



Doncaster (Cambridge). 



1677) Morgan, T. H., Notes on Two Crosses Between Different 

 Üipgs ot* Pi^Göns 



(Biological Bulletin 21,4. p. 215— 221. 6 figs. 1911.) 



1. Cross between a white fantail § and a „swallow" q*. The fantail 

 used had 32 tail feathers, the swallow 12. Seven young were reared with 17, 

 12, 13, 15, 14, 13, 13, tail feathers, an intermediate condition with a distinct 

 approach to the normal. Only four birds were reared in the F 2 generation; 

 each had 12 feathers in its tail. The number is too small for positive con- 

 clusions. The inheritance of some other characteristics is also noted. 



2. Cross between a Turbit and a Starling. Two hybrids were produced 

 and from these eight F 2 birds were reared. The reversed feathers on the 

 breast of the pure turbit did not reappear in any of the F 2 birds. „The 

 result is like that of the number of tail feathers in the fantail-swallow cross, 

 but here also the numbers are too small to make any conclusion possible, 

 however significant the absence of reversed feathers may appear." 



Lillie (Chicago). 



1678) Harris, J. A., The distribution of pure line means. 



(Amer. Nat. 45. p. 686— 700. 1911.) 

 A criticism of a recent paper by Roemer who, from investigations on several 

 characters in peas, concluded that the population contains various biotypes 

 which arrange tbemselves in frequency according to Quetelet's Curve. After 

 an analysis of these results the writer concludes that the material probably 

 all belonged to one „pure line", but that if it did not the results are opposed 

 to rather than confirmatory of Johannsen's theory. Gates (London). 



