MOOR-BUZZARD— MOOR-HEN 589 



result of arrested development of the anterior cranial vesicle. 

 Irregular growth of the Amnion frequently has a disturbing in- 

 fluence upon various parts of the embryo, and thus abnormalities of 

 the tailfold (Embryology, p. 201) produce hind limbs abnormal in 

 shape and position, a crooked vertebral column and so on. Double 

 or treble monsters, partial or even perfect twins, or triplets, may be 

 due to any one of three causes : — two or three yolks, each with its 

 own blastoderm (p. 200) in one common shell ; two blastoderms 

 with one yolk ; or one blastoderm upon a single yolk, split by a 

 subsequent injury, each portion of it producing a more or less 

 complete counterpart of an embryo or portion of it. M. Dareste 

 has been able to shew beyond doubt that portions of the blasto- 

 derm artificially split off", or even parts of more advanced embryos 

 will occasionally continue growing into a part at least of that 

 organ, of which the respective embryonic cells were the normal 

 substratum ; in the case of two blastoderms upon a single yolk, 

 complete though more or less united embryos will be the result. 

 According to the present state of our knowledge it is not justifiable 

 to explain partly multiple monstrosities by the assumption of a fusing 

 of originally separate embryos, but by a splitting of the blasto- 

 derm, and if that takes place very early and is complete, each of 

 its halves, which in Mammals have little or no yolk, may produce 

 an independent embryo, so that in such a case the flippant saying 

 that "A twin is only the other half" happens to be true. 



MOOR-BUZZARD, the common name in England, in days 

 when the bird was not scarce, for what is called in books the 

 Marsh-HARRIER. 



MOOR-COOK, MOOR-FOWL and MOOR-POULT, old English 

 names of the bird now well known as the Red GROUSE ; but 



MOOR-HEN is the commonest name of a common bird, often 

 called AVater-hen, and in books sometimes Gallinule. An earlier 

 English name was Moat -hen, which Avas 

 appropriate in the days when a moat was 

 the ordinary adjunct of most consideralile 

 houses in the country, and this species 

 its ordinary denizen. It is the Gallinula 

 cidorovus of ornitholosrists, and so well .. />f* ^, • x 



J- " . . Moor-hen. (After Swamson.) 



known as hardly to need description. 



About the size of a small Bantam -hen, but with the body 

 much compressed, as is usual with members of the Family 

 Rallidss (Rail) to which it belongs, its plumage above is of a 

 deep olive-brown, so dark as to appear black at a short distance, 

 and beneath iron-grey, relieved by some white stripes on the 

 flanks, with the lower tail-coverts of pure white — these last being 

 very conspicuous as the bird swims. A scarlet frontlet, especially 



