Descendenz u. Hybriden. 323 



des erreurs que le Ref. avait signalees lors de la premiere 

 edition.*) A. Giard. 



Pearson, Karl, Alice Lee. E. Warren, Agnes Fry, and Cecily 

 D. Fawcett, OnthePrinciple of Homotyposis and its 

 Relation to Heredity, to the Variability of the 

 Individual, and to that of the Race. I. Homoty- 

 posis in the Vegetable Kingdom. (Proc. Royal Soc. 

 London. 1901.) 



By Homotypes are meant such organs as hairs, scales, 

 buds, leaves, flowers, fruits, ova and spermatozoids, when no 

 trace of diiferentiation in function can be detected between 

 them, and the question propounded is: „Is there a greater 

 degree of resemblance between homotypes from the same indi- 

 vidual than between homotypes from separate individuals?" 

 The principle of the lik^.ness and diversity between homotypes 

 is termed Homotyposis. The following series were exami- 

 nated : a) Leaflets from Compound leaves of the ash from different 

 localities. The results show homotyposis to be a racial character 

 of considerable constancy. b) Veins in leaves of the spanish 

 Chestnut. Homotyposis increased with heterogeneity of age and 

 locality. c) Veins in leaves of Beach. d) Prickles on leaves of 

 Holly. e) Stigmatic bands in Capsule of Papaver Rhoeas from 

 different localities and segmentation of the seed vessels in 

 Nigella and Malva. There is a differentiation between the 

 capsules on the main and side shoots and a consequent 

 weakening of homotyposis. f) Numbers in the foliar whorls of 

 Asperula odorata. These are known to be differentiated, and 

 homotyposis is much weakened. g) Sori on fronds of ferns. 

 These are much affected by environment and age, and homo- 

 typosis is weakened. h) Veins in the Tunic of Allium Cepa. 

 i) Seeds in pods of the broom. The general result from seeds 

 in pods of the Leguminosae is that homotypic intensity is halved 

 when dealing with a character associated with fertilization. 

 The possibility that fraternal correlation is due to homotyposis 

 in the characters of ova and spermatozoa is suggested. If this 

 be true the mean value of fraternal correlation should be equal 

 to the mean intensity of homotypic correlation, and Statistical 

 enquiry shows this to be very nearly the case, and the author 

 is inclined to take the view that heredity is merely a phase of 

 homotyposis and that the latter approximates to a certain value 

 throughout living forms. 



The individual Variation expressed as a percentage of the 

 racial Variation has a mean value of 87°/ and it would there- 

 fore seem idle to speak of Variation as the result of sexual 

 reproduction. It exists in füll where an organ throws vegetati- 

 vely undifferentiated like organs, and the blood-corpuscles of a 



*) Voir A. Giard. La direction des etudes biologiques en France 

 etc. 2. edit. 1896, et B u 1 1. s c i e n t. F r. e t B elg. T. XXVII. 



21* 



