( 398 ) 



The Plantaris (= Soleus) is in no way [iccnliar : it is a fleshy muscle arising 

 from the head of tibia jnst beneath the insertion of the semitendinosus ; it is 

 inserted by a long tendon on to the cartilage through which the flexor tendons 

 glide. 



The three Flexores perforati (of digits II., III., IV.) are connected at tlieir 

 origin from the femur with each other and with the flexor profundns. Their 

 tendons, however, separate early, as is usual. Tlie strong ambiens tendon is 

 definitely attached to the fl. perf II., and to that only ; it does not give off slips, 

 as Mitchell has figured and described in various liirds to the two other muscles, 

 making up the jierforatus complex. Furthermore, three small tendinous bands, 

 accompanied by muscle fibres, and forming a tiiin flat sheet of tissue, are continuous 

 with the ambiens tendon above, and appear to be in connection at the other end 

 with the short arm of the biceps sling, and to arise from the fibula. I look njjon 

 this sheet of muscle and tendon as a second head of the flexor in qnestion, and 

 as corresponding to the fibular head of birds, such as Sijcticorax. If this be so, 

 Mitchell's contention that the ligamentous head in question is a rudimentary ambiens 

 is not so certain as it seemed to be, for both occur in ApU'rijx. I found the same 

 state of affairs in ^1. haaati. 



The Flexor perfo)-anx et perj'oratus dnj. 111. arises partly from the head of the 

 tibia, partly from the patellar ligament, and finally from a broad sheet of glistening 

 tendon which nnites it w-ith the adjacent gastrocnemius head, and from the middle 

 of which also arises the next muscle to be described. This broad sheet of tendon 

 ends below to form a turned-up margin continuous with the long head of the 

 biceps sling. The tendon of the mnscle is joined by a viuculum to the perforatns 

 tendon of the same digit. 



The Flexor perj'orans et perforatum dig. II. is a smaller muscle than the last ; 

 it lies between it and the outer head of the gastrocnemins. It arises, as already 

 stated in describing the last muscle, from the femur and the septum between itself 

 and the last. 



The Flexor /lallucis longus arises by a principal head from the intercondylar 

 region in conjunction with some of the other flexor muscles, and by a small slender 

 entirely muscular additional head from the posterior surface of the outer condyle : 

 the two soon unite, and from their tendon is given off, as Garrod has described, 

 a thin tendon to the Hallux before it becomes fused with the tendon of tlie 

 flexor profundns. 



The Flexor profundus springs from the upper part of the sliaft of the tibia 

 and fibula, both beneath the Popliteus and also from its fibular tendons ; there 

 is a second and smaller head of origin from the outer condyle of the femur. Its 

 tendon fuses with that of the last muscle, and the conjoined tendon thus formed 

 s]ilits into three tendons for digits II. — IV. 



MUSCI>ES OF THE FoIiK LiMB. 



The muscles of the fore limb have been, as already exjilained, described in 

 great detail for Apteryx by more than one observer. I feel it therefore uimecessary 

 to do more than indicate some few differences that I have observed in several 

 species. Considering that the wing is the most degenerate organ of Apteryx, and 

 that the muscles are naturally sharing the fate of the dwindling bones, it does not 

 seem permissible to dwell much \\\)u\\ such varintions as their different degrees of 

 degencracv show. 



