_The other parent communicates the posterior part of the head, the cerebel situated within the skull immediately above its junction with the back of the neck, and the whole of the locomotive system_; (the bones, ligaments and muscles or fleshy parts.) The resemblance to that parent is consequently found in the back head, the few more movable parts of the face, as the external ear, under lip, lower part of the nose, eyebrows, and the external forms of the body, in so far as they depend on the muscles as well as the form of the limbs, even to the fingers, toes and nails. * * It is a fact established by my observations that in animals of the _same variety, either the male or the female parent_ may give _either series of organs_ as above arranged--that is _either_ forehead and organs of sense, together with the vital and nutritive organs, _or_ back head, together with the locomotive organs." To show that among domesticated animals organization is transmitted by halves in the way indicated, and that either parent may give either series of organs, he cites among other instances the account of the Ancon sheep. "When both parents are of the Ancon or Otter breed, their descendants inherit their peculiar appearance and proportions of form. When an Ancon ewe is impregnated by a common ram, the progeny resembles wholly either the ewe or the ram. The progeny of a common ewe impregnated by an Ancon ram follows entirely in shape the one or the other without blending any of the distinguishing and essential peculiarities of both. 'Frequent instances have occurred where common ewes have had twins by Ancon rams; when one exhibited the complete marks and features of the ewe and the other of the ram. The contrast has been rendered singularly striking when one short legged and one long legged lamb produced at a birth have been sucking the dam at the same time.' As the short and crooked legs or those of opposite form, here indicate the parent giving the locomotive system, it is evident that one of the twins derived it from one parent and the other twin from the other parent;--the parent not giving it, doubtless communicating in each case, the vital or nutritive system." Where the parents are of different varieties or species, Mr. Walker says, "The second law, namely, that of CROSSING, operates where each parent is of a _different breed_, and where, supposing both to be of equal age and vigor the _male_ gives the _back head_ and _locomotive organs_, and the _female_ the _face_ and _nutritive organs_." After giving numerous illustrations from facts and many quotations from eminent breeders, he says, "thus, in crosses of cattle as well as of horses, the male, except where feebler or of inferior voluntary and locomotive power, gives the locomotive system, the female the vital one."