[22] Domestic pigeons pair readily with the allied _C. œnas_ (Bechstein, ‘Naturgesch. Deutschlands,’ B. iv. s. 3); and Mr. Brent has made the same cross several times in England, but the young were very apt to die at about ten days old; one hybrid which he reared (from _C. œnas_ and a male Antwerp Carrier) paired with a Dragon, but never laid eggs. Bechstein further states (s. 26) that the domestic pigeon will cross with _C. palumbus, Turtur risoria,_ and _T. vulgaris,_ but nothing is said of the fertility of the hybrids, and this would have been mentioned had the fact been ascertained. In the Zoological Gardens (MS. report to me from Mr. James Hunt) a male hybrid from _Turtur vulgaris_ and a domestic pigeon “paired with several different species of pigeons and doves, but none of the eggs were good.” Hybrids from _C. œnas_ and _gymnophthalmos_ were sterile. In Loudon’s ‘Mag. of Nat. Hist.,’ vol. vii. 1834, p. 154, it is said that a male hybrid (from _Turtur vulgaris_ male, and the cream-coloured _T. risoria_ female) paired during two years with a female _T. risoria,_ and the latter laid many eggs, but all were sterile. MM. Boitard and Corbié (‘Les Pigeons,’ p. 235) state that the hybrids from these two turtle-doves are invariably sterile both _inter se_ and with either pure parent. The experiment was tried by M. Corbié “avec une espèce d’obstination;” and likewise by M. Mauduyt, and by M. Vieillot. Temminck also found the hybrids from these two species quite barren. Therefore, when Bechstein (‘Naturgesch. Deutschlands Vögel,’ B. iv. s. 101) asserts that the hybrids from these two turtle-doves propagate _inter se_ equally well with pure species, and when a writer in the ‘Field’ newspaper (in a letter dated Nov. 10th, 1858) makes a similar assertion, it would appear that there must be some mistake; though what the mistake is I know not, as Bechstein at least must have known the white _variety_ of _T. risoria_: it would be an unparalleled fact if the same two species sometimes produced _extremely_ fertile, and sometimes _extremely_ barren, offspring. In the MS. report from the Zoological Gardens it is said that hybrids from _Turtur vulgaris_ and _ suratensis,_ and from _T. vulgaris_ and _Ectopistes migratorius,_ were sterile. Two of the latter male hybrids paired with their pure parents, viz. _Turtur vulgaris_ and the Ectopistes, and likewise with _T. risoria_ and with _ Columba œnas,_ and many eggs were produced, but all were barren. At Paris, hybrids have been raised (Isid. Geoffrey Saint-Hilaire, ‘Hist. Nat. Générale,’ tom. iii. p. 180) from _Turtur auritus_ with _T. cambayensis_ and with _T. suratensis_; but nothing is said of their fertility. At the Zoological Gardens of London the _Goura coronata_ and _victoriæ_ produced a hybrid which paired with the pure _G. coronata,_ and laid several eggs, but these proved barren. In 1860 _Columba gymnophthalmos_ and _maculosa_ produced hybrids in these same gardens.