Note 20 — Chapter XVIII · ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED CONDITIONS OF LIFE: STERILITY FROM VARIOUS CAUSES.
Reading edition
Rengger ‘Säugethiere,’ etc., s. 276. On the parentage of the guinea-pig, see also Isid. Geoffroy St.-Hilaire, ‘Hist. Nat. Gen.’ I sent to Mr. H. Denny of Leeds the lice which I collected from the wild aperea in La Plata, and he informs me that they belong to a genus distinct from those found on the guinea-pig. This is important evidence that the aperea is not the parent of the guinea-pig; and is worth giving, as some authors erroneously suppose that the guinea-pig since being domesticated has become sterile when crossed with the aperea.