168 BLASTOGENIC VARIATIONS. 



ous intermediate forms in such genera as Melitcea, 

 Zygoma, and Agrotis may be accounted for in this man- 

 ner. Cases of simple pairing between distinct species 

 of the two former genera have been observed by the 

 author [Standfuss] in nature." 



Upon Echinoids, the author has made numerous 

 crosses and reciprocal crosses.* Eight species were 

 worked with, and of the 56 possible crosses, 41 were at- 

 tempted. Of these, 22 yielded larvae of 8 days' growth. 

 In only one cross did any of the larvae incline towards 

 the paternal type, and the majority of those then ob- 

 tained were more or less intermediate. In nine other 

 crosses also they were more or less intermediate in char- 

 acter, whilst in the remaining twelve they were of the 

 maternal type. A few of the larvae exhibited char- 

 acters which were not present in either parent. 



Upon members of the Mammalian and Avian King- 

 doms, a very large number of crossing experiments 

 have been made, and frequently with success, but the 

 observations are not sufficiently extensive to admit of 

 generalisations. The most interesting experiments of 

 recent years are those of Professor Ewart, upon zebra 

 hybrids.f By crossing mares of various sizes (11 to 15 

 hands) with a zebra stallion, nine hybrids were obtained 

 altogether. Also Professor Ewart had in his possession 

 three hybrids out of zebra mares, one having for his 

 sire a donkey, whilst the other two were sired by ponies. 

 The hybrids showed a " curious blending of characters, 

 derived apparently partly from their actual and partly 



*Phil. Trans. Roy. Soc., 1898, B. p. 483, and Arch, f . Entwick- 

 elungsmechanik. , Bd. ix. p. 468, 1900. 

 f " The Penycuik Experiments." 



