tJie M'ulicife load. 133 



water as Is usual witli batrachiaiis. Ifc is to be expressly 

 noticed that these lumps on the thumbs or arms of male toads 

 and frogs are not merely pigmented swellings, but are pads 

 bearing numerous minute horny black spines, which are used 

 in holding tlie female in the water. Tlie figures which 

 Kam merer gives are quite inadequate, and as they merely 

 indicate a dark patch on the thumbs it is not possible to form 

 any opinion as to the nature of the structure they represent. 



"The systematists who have made a special study of 

 Batrachia appear to be agreed that Alytes in nature does not 

 liave these structures ; and when individuals possessing them 

 can be produced for inspection it will, I think, be time to 

 examine the evidence for the inheritance of acquired characters 

 more seriously. I wrote to Dr. Kammerer in July 1910, 

 asking him for the loan of such a specimen'^, and on visiting 

 the Biologische Versuchsanstalt in SeptemlDer of the same 

 year I made the same request ; but hitherto none has been 

 produced. In matters of this kind much generally depends 

 on interpretations made at the time of observation ; here, 

 liowever, is an example which could readily be attested by 

 preserved material. I notice with some surprise that in a 

 later publication [Kammerer, 4] on the same subject no 

 reference to the development of these structures is made. 

 As these .... would be of special value in such a diagnosis, 

 the omission of any allusion to them calls for explanation. 

 Kammerer claims the evidence as proof of Mendelian segre- 

 gation in regard to an acquired character, the first example 

 recorded. Pending a repetition of the experiment, there is no 

 more to be said.''' 



A last remark. Kammerer takes it for granted that the 

 aquatic parturition, resulting in a strong reduction in the size 

 of the vitelline sphere, such as he claims to have artificially 

 induced in Alytes, is a case of atavistic reversion (1, p. 70 ; 

 4, pp. 96, 105). Has he given sufficient thought to this 

 important question? Is he aware of how great a number of 

 batrachians, not necessarily with direct development and quite 

 irrespective of their systematic position, produce eggs with 

 large vitellus, so that, when our knowledge of tropical forms 

 is more advanced, such a type of eggs may no longer have to 



* " In replj^ to my letter, Dr. Kammerer, -who was then away from 

 home, very kindly replied that he Avas not quite sure whether he had 

 killed specimens of Alytes with ' Brunift.&chidelen ' or whether he only 

 had living males of the fourth generation, but that he would send illus- 

 trative material." 



