56 Proceedings of the Royal Irish Acadom 



IX. — On some Points ix Bird Mtologt. By A. Macalister, M.B., 

 Professor of CoroparatiYe Anatomy, Dublin "Cmversity. 



[Eead April 27, 187-i.] 



The difficulties in the classification of birds liave led many recent 

 zoologists to seek for special principles of classification 'vvliereby to 

 subdivide that exceedingly compact and natui'al class ; but, excej^t the 

 skull- classification of Professor Huxley, there has not been anything 

 proposed more satisfactory than the old Cuvierian arrangement. 



The active and observant prosector of the Zoological Society of 

 London, Mr. A. H. Grarrod, has proposed two new points as bases of 

 classification — one, the arrangement of the nasal bones and their siu'- 

 rounding parts ; the second, the varieties in the muscular system. 



The author of the " Ornithologiskt System" has used some of these 

 muscular characters as of taxonomic value ; but jNIr. Garrod, from an 

 extensive range of dissections, has tried to use the presence or absence 

 of some muscles as elements in classification. 



The muscles used thus by llr. Garrod are: 1st, the caudo-femo- 

 ralis — a muscle which passes from the tail to the linea aspera ; 2nd, 

 the quadratus femoris, which extends from the ischium to the femui', 

 above the last (this muscle Mr. Garrod calls accessory femoro-cau- 

 dal ; but it is most probably the homologue of the quadratus femoris, 

 as its nerve arises high up from the roots of the nervus tibialis) ; 3rd. 

 the semitendinosus ; 4th, the femoral head of the semitendinosus; 5th, 

 the long muscle (called rectus by Meckel, gracilis by Cuvier, Owen, 

 and Huxley, but named ambiens by Mr. Garrod). 



Mr. Garrod divides birds into two great groups— those with and 

 those without a rectus femoris. Those with he calls Homalogonati ; 

 those without he calls Anomalogonati. Among the Homalogonati, 

 however, he includes the Stork, Pelican, Jabiru, and Ardeidae, as well as 

 the Owl, Grebes, and Auks, none of which possess such a muscle. 



Among the Anomalogonati there is not much of myological varia- 

 tion. Macrochires have no quadi'atus nor semitendinosus, and this 

 Mr. Garrod has noted. Coccygomorpha3 and Passerinee resemble each 

 other in having no quadratus but a semitendinosus ; but while Cu- 

 culus has a rectus, and belongs to the next group, the others of the 

 order do not. If the rectus be of true taxonomic value, the Ardeidae, 

 Podicipidffi, Alcidae, and Phoeuicopteridse should be introduced here. 



The Homalogonati are more variable. The femoro- caudal is absent 

 in the Ostrich, Grebe, Otis, and Plamingo; in the last-named we failed 

 to find a rectus femoris, though Mr. Garrod has found one ; so this 

 muscle appears to be subject to variety. The Pelican, likewise, we 

 found to have no femoro-caudal, though Sula has one, and also Phala- 

 crocorax. The quadratus femoris is absent in Parrots, PeKcans, 

 and Storks, according to Mr. Garrod ; but here there are also ele- 

 ments of varietv; for in Pelicanus onocrotcdus and Ciconia alba I have • 



