210 ON THE LATE PROF. GARROD*S CONTRIBUTIONS 



amliens muscle is, in my mind, the key to the whole," and that, not 

 because of its own intrinsic importance, but because its presence is always 

 associated with peculiarities in other parts never found in any Anoma- 

 logonatous bird. That the same combinations of three or four different 

 characters should have arisen independently in different birds is so ex- 

 tremely improbable, that we can hardly ascribe these similarities in com- 

 binations of characters to any other cause than to blood-relationship, the 

 expression of which is now unanimously accepted as the true end of all 

 biological classifications. 



" The facts disclosed by a study of the myology of birds do not, without 

 extraneous assistance, place the families in their true relationship to one 

 another. Because the same muscles are present in two families of birds, 

 it cannot therefore be said that their kinship is extremely close, or the 

 reverse .... It is therefore necessary to look around to find, if possible, 

 myological characters which have some definite relation to equally well- 

 marked pterylographic, visceral, or osteological peculiarities " (P. Z. S. 

 1874, p. 114). As already insisted on, it was in this combination of 

 characters that Prof. Garrod trusted to find the true " key " to the 

 question. 



To return to facts, no bird which is " Anomalogonatous " has ever an 

 accessory femoro-caudal muscle ; that is, the letter B never enters its 

 formula. Again, no bird that is Anomalogonatous has ever a tufted oil- 

 gland and caeca, though this combination is nearly always found in the 

 Homalogonatous birds. So much so is this the case, that there are only 

 Ibis, 1881, nuie groups of Homalogonatous birds that have not this mentioned 

 P- 29. combination *, and in two of these the exception is caused by the entire 

 absence of the oil-gland (in the OtididaB and the Struthiones). Of the 

 remaining seven, in which the caeca and a tufted oil-gland are not 

 correlated, I find, by tabulation, that four always have the ambiens 

 muscle developed, whilst the remaining three have it present in at least 

 some of their members. Of these latter, moreover, two have the 

 accessory femoro-caudal (B) always present ; so that it is only certain 

 Parrots which have a formula like that of any anomalogonatous bird (for 

 it must be remembered that in several Parrots the ambiens muscle is 

 present). This fact will be made clearer by the accompanying table, 

 containing the names of the three main groups of the Anomalogonatae, 

 Ibis, 1881, followed by those of the seven groups above mentioned as the exceptions 

 P- 30. to the combination of caeca and a tufted oil-gland amongst the Homalo- 

 gonatae. 



Thus, of the whole series of Homalogonatous birds, not one, except 

 certain Parrots (the most specialized, no doubt, of all that series), has 



* One or two genera in various families, as e. g. Cancroma, have also lost the oil- 

 gland tuft. As, however, all the allied genera retain it, these slight exceptions in no 

 way invalidate Prof. Garrod's argument. 



