_Sub-race II. Common Frill-back_ (die Strupptaube).—_Beak rather longer than in the rock-pigeon; feathers reversed._—This is a considerably larger bird than the rock-pigeon, and with the beak, proportionally with the size of body, a little (viz. by ·04 of an inch) longer. The feathers, especially on the wing-coverts, have their points curled upwards or back-wards. _Sub-race III. Nuns_ (Pigeons coquilles).—These elegant birds are smaller than the rock-pigeon. The beak is actually 1·7, and proportionally with the size of the body ·1 of an inch shorter than in the rock-pigeons, although of the same thickness. In young birds the scutellæ on the tarsi and toes are generally of a leaden-black colour; and this is a remarkable character (though observed in a lesser degree in some other breeds), as the colour of the legs in the adult state is subject to very little variation in any breed. I have on two or three occasions counted thirteen or fourteen feathers in the tail; this likewise occurs in the barely distinct breed called Helmets. Nuns are symmetrically coloured, with the head, primary wing-feathers, tail, and tail-coverts of the same colour, namely, black or red, and with the rest of the body white. This breed has retained the same character since Aldrovandi wrote in 1600. I have received from Madras almost similarly coloured birds. _Sub-race IV. Spots_ (die Blasstauben; pigeons heurtés).—These birds are a very little larger than the rock-pigeon, with the beak a trace smaller in all its dimensions, and with the feet decidedly smaller. They are symmetrically coloured, with a spot on the forehead, with the tail and tail-coverts of the same colour, the rest of the body being white. This breed existed in 1676;[22] and in 1735 Moore remarks that they breed truly, as is the case at the present day. _Sub-race V. Swallows._—These birds, as measured from tip to tip of wing, or from the end of the beak to the end of the tail, exceed in size the rock-pigeon; but their bodies are much less bulky; their feet and legs are likewise smaller. The beak is of about the same length, but rather slighter. Altogether their general appearance is considerably different from that of the rock-pigeon. Their heads and wings are of the same colour, the rest of the body being white. Their flight is said to be peculiar. This seems to be a modern breed, which, however, originated before the year 1795 in Germany, for it is described by Bechstein.