ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 339 



Expulsion of Eggs in Entelurus aequoreus.* — F. Guitel finds from 

 post-mortem observations that the ova are expelled from the cloaca in 

 two ribbons, about 75 mm. long, and consisting of a single layer of 

 3-5 rows. These ribbons are afterwards fixed to the abdomen of the 

 male in precisely the same position as they had in the ovaries. There 

 is a slight median keel along the abdomen. 



Inheritance of Eye-colour in Man.f — C. C. Hurst has studied the 

 eye-colours of a number of parents aud their offspring in a Leicestershire 

 village, and finds that there are at least two discontinuous types of iris in 

 man. There is the duplex type, with both anterior and posterior pig- 

 ments, as in ordinary brown eyes, and there is the simplex type, with 

 posterior pigment only, the anterior pigment being absent, as in clear 

 blue eyes. The simplex type behaves as a Mendelian recessive to the 

 duplex type, which is dominant. The unit characters concerned are 

 evidently presence (duplex) and absence (simplex) of anterior pigment 

 on a basis of posterior pigment, presence being dominant. The duplex 

 and simplex types can be distinguished at any age. Similar conclusions 

 have been reached independently by Davenport. 



Inheritance of Coat-colour in Rats.J — GL P. Mudge finds that 

 black is dominant to albinism, but the dominance is not complete, some 

 ventral white being always present. It is theoretically conceivable that 

 the incompleteness of the dominance is due to the influence of the 

 factor .y ( = absence of self -pattern) brought in by the albino. 



Expected types do not all always appear in any one litter of young, 

 and frequently not until the third litter. Predictions based upon the 

 doctrine of gametic purity and of dominance have not in the author's 

 experiments been falsified by the appearance of any unpredicted types. 



The conception (hitherto a matter of deduction) that albinos are 

 the bearers of hidden factors, has been ocularly demonstrated for the 

 piebald, " Irish," and self-patterns. Four types of albinos have been 

 shown to exist. 



Completely self -black extracted forms are homozygous for black. 

 Self-grey types may carry both black and piebald recessive. Piebald 

 black-white types may be homozygous for black and piebald, or may 

 carry albinism recessive. 



Externally considered, similar zygotes may have a different gametic 

 constitution. Zygotic characters alone are not, therefore, a safe basis 

 for prediction. 



With regard to the number of allelomorphs for colour and pattern, 

 the evidence shows that there are two pairs for each, i.e., presence and 

 absence of greyness, presence and absence of blackness, presence and 

 absence of selfness, and presence and absence of piebaldness. 



Experimental Estimation of the Theory of Ancestral Contribu- 

 tions in Inheritance^ — A. D. Darbishire has made experiments with 

 peas with the object of finding out if the proportions in which characters 



* Arch. Zool. Exper., ix. (1908) Notes et Revue, No. 2 pp. xxiv.-ix. (1 fig.). 



t Proc. Roy. Soc, Series B, lxxx. (1908) No. B537, pp. 85-96. 



J Tom. cit., pp. 97-121. 



§ Op. cit., lxxxi. (1909) No. B545, pp. 61-79. 



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