624 



DR. ROLLESTON ON THE HOMOLOGIES OF CERTAIN 



by the great excess which the number made up by the adductores and the obturatores 

 shows when compared with that of their homotypes the coraco-brachiales. It furnishes 

 us with a fresh illustration of the principle laid down by Mr. Parker (Shoulder-Girdle, 

 p. 7, note), to the effect that "the hip-girdle is always, in the higher classes, more 

 complete as to mere mass, and lower in type morphologically, than the shoulder-girdle." 



Tabular View of Muscular Homologies suggested in this Paper. 



Name of Muscle in Mammal. 



Homologue in 

 Upper Extremity of Bird 



Homologue in 

 Upper Extremity of Reptile. 



Pectoral is major. 



Ditto. 



Ditto. 



Serial Homologue, 





Pectoralis minor. 



Essentially the upper or an- 

 teriorly inserted fascicles of the 

 deep layers of pectoralis major. 



Ditto 



Subclaviu*. 



In mammals only is it of 

 subordinate importance to the 

 spinati. 



Coracobrachial is brevis s. rota- 

 tor humeri of Wood. 



Pectoralis secundus s. levator hu- 

 meri. 



Fascicle lettered ei in figr. 3 P 



•• ( iratiH^' of Mivart, as described 

 in Iguana, P. Z. S. 1807. 



? 



Epicoraco-hmnvral of Mivart, as 

 described in Echidna and 

 Iguana, 1. c. 

 Amphibian/wrs clavicuhiris del- 

 toid* "i as described by Ecker, 

 cleido-hu meralis of Pfeiffer. 



Inner and deeper head oipecti- 

 neus, supplied by obturator 



nerve. 



Coraco-brachialis medius. 

 Coraco-brachialis longus. 



Deltoides inferior of Meckel. 

 No. xx. of Schoepss, Meckel's 

 Archiv, 1829. 



Upper part of coraco-brachialis 

 lying superiorly to tendon of 

 biceps. 



Upper fascicles of obturator ex- 

 ternum. 



Pectoralis tertius s. coraco-bra- 

 chialis inferior. 

 No. xvi. Schoepss, /, c. 



Deep portions of cwaco-brachi- 

 alis, in Monotreme. 



(See Mivart, p. 385, Linn. Soc. 

 Trans, vol. xxv.) 



Deltoid. 



Coraco-brachialis supeiHor. 

 No. xvii. Schoepss suggested as 

 homologue by Mivart, /. c. 



Middle and longer portions of 



anterior coraco-brachialis. 



Rest of obturator crternus and 

 adductors. 



Ditto 



Represented in birds by the 

 deltoides externus of Meckel, 

 no. xix. Schoepss, by the del- 

 toides superior of Meckel, 

 no. xviii. of Schoepss, and by 

 the smaller levator humeri of 

 the Fowl. 



Deltoid. 



Infraspin atus, 

 natus. 



and 



supraspi- 



Not found in birds as differ- 

 entiated slips. 



Teres minor. 



Essentially a deep portion 

 of posterior part of deltoid. 



Not 

 except 

 titse ? 



differentiated in birds. 

 Emu and other Ra- 



Scapulo-h timer al. 



Essentially a part either of 

 subscapularis or teres major. 



Present in Fowl, Goose, Spar 

 row-Hawk, Buzzard. 



Absent in Pigeon. 



Teres 



major, 



Obturator intern us. 

 Thin muscle is neversupplied 



by the obturator nerve. 



Outer head of pntitwus, sup- 

 plied by anterior crural 

 nerve or its internal cuta- 

 neous branch. 



8uprascamilar%8 9 " infraspina 

 tus," Mivart. 



Iliarus, exclusively of part spe- 

 citi 11 low. 



Differentiated is Crocodile and 



Chamiekon. 



Musntlus iliaem interims minor 



of Luachka, Anat. Mensch. 

 ii. 2. 131. 



Pres. nt in Crocodile. 

 Absent as a differentiated 

 p in some saurians. 



Very large in birds. 



Mu8culu$ scansorius. 



Present in Crocodile. 

 Absent as differentiated slip in 

 some saurians, as Chamaeleon. 



Tensor fascice femoris 



