MYOLOGY OF THE ORNITHORHYNCHUS. 161 



the middle of that bone quite to the inner condyle. Above, its inser- 

 tion is in relation with that of the pectinseus ; below, with femoral 

 head of gastrocnemius and insertion of the semi-tendinosus. It is 

 almost a pure extensor, having little adductorial action, if any. 



Adductor longus. A prismatic muscle, with one surface superficial 

 (except that it is covered by the gracilis~) r and one edge and two sur- 

 faces wedged down between adductor magnus and brevis. It arises 

 by itself from the horizontal ramus of the pubis, a little toward the 

 median line from the articulation of the marsupial bone, and very 

 near the symphysis. It has definite abrupt insertion by a short ten- 

 don into the inner condyle, between the insertions of the last and the 

 next. It is a pure adductor, and a strong one. 



Adductor brevis. A flattened fusiform muscle, lying anterior to the 

 last, upon the pectinceus, which separates it from ps. magnus and 

 iliacus. It arises from the process upon the horizontal ramus pubis 

 at outer corner of articulation of the marsupial bone, and runs straight 

 to a definite insertion, by a short, roundish tendon, into the inner con- 

 dyle, just above the insertion of the last. A pure adductor. 



Pectinceus. A very small, flattened-oval muscle arising by a terete 

 tendon from the deep notch at base (in front) of the remarkable pec- 

 tinseal eminence, passing outward and backward upon the psoas mag- 

 nus, overlaid by adductor brevis, to be inserted, by a rather long, 

 narrow, thin, fascia-like tendon into the postero-internal ridge of 

 the femur, near the middle of the bone. It is a flexor, and evertor 

 femoris, with action not very different from that of psoas, but feeble. 



Of these four adductorial muscles, it may be said briefly, that the two 

 middle ones are adductors proper, the action of which may merge into 

 either flexion or extension, in extreme postures of the thigh ; that the 

 first described is always extensor and barely adductor, while the last 

 is always flexor and barely adductor. 



It will be observed that the usual essential arrangement of four 

 adductorial planes is preserved, the hind extremity offering no such 

 deviation in this respect as the fore does in its division of coraco- 

 brachialis into two, and their high development; a circumstance 

 highly favoring the reference of the four adductors to coraco-brachialis 

 and pectoralis major, that has been made by Wilder. * The question 

 whether the adductors are, or the pectinaeus is, to be referred to pec- 

 toralis, and conversely, probably finally hinges upon determination of 

 pubis as == coracoid, or as = clavicle. The present indication, from 

 the extensive development of two coraco-brachiales, is, that these are 

 represented in the hind limb by the adductors proper, leaving pecti- 

 nseus as the correlative of the pectoralis. 



*Op. cit. p. 32. 



