BY WILLIAM A. HASWELL, M.A., B.Sc. 399 



to be not a universal modification ; but the correctness of my 

 observations can be verified by anyone, and it is a point whose 

 importance in the classification of the Columba) will probably 

 prove to be considerable. 



3. The absence of the glutasus externus and the presence of 

 the adductores brevis et longus, the semitendindosus and semi- 

 membranosus. With reference to this point Dr. Gradow states : — 

 " Now the m. gluteus externus (j=(jliif. anterior) is generally very 

 small, but plainly visible in many birds, such as Pigeons, Passerine 

 birds, &c., and not absent as stated by Mr. Haswell," (i.e. as I 

 take it, " though very small in many birds such as Pigeons, 

 Passerine birds &c., is plainly visible," etc.). That this musele, 

 though well developed in many families, is extremely small in 

 others is a well-known fact ; but in the Pigeon it is entirely absent 

 as a separate muscle, as was long ago pointed out by Gi-arrod.* 

 In regard to the four muscles whose presence is specially noted, 

 Dr. Gadow goes on to say — " The four other muscles are well- 

 developed in most birds as Prof. Grarrod has stated over and 

 over again, and as the dissection of any fowl will shew." I may 

 here quote my own words in the paper alluded to. " The adductor 

 hrevis, adductor longus, semlmemhranosus, semitendinosus and 

 accessory semitendinosus are all present. The significance of these 

 muscles has been pointed out by Mr. A. H. Garrod (" On certain 

 muscles of the Thigh of Bird and their value in classification, P. 

 Z.S., 1873 and 1874)." This surely is plain enough. Prof. 

 Garrod found that the absence or presence of certain muscles of 

 the thigh was characteristic of the various major groups of birds. 

 Indicating each of these muscles by a letter he was able to give 

 a myological f ormulr for each, and these formulae he found to be 

 of some value in the determination of afiinities. Surely then this 

 formula is of sufiicient importance to be quoted in an enumeration 

 of the myological characters of the Pigeons. But Dr. Gadow not 



* Vide his " Collected Scientific Papers/' p. 210, or P.Z.S., 1S74, p. 258. 

 Al 



