EEPOET ON THE SPHENISCID^. 113 



5. Semi-tendinosus. 



Biceps (part of), Vicq d'Azyr, 1774, p. 507, Xo. 3. 

 Troisihne Jlwhisseur de lajarnhe, Cuvier, vol. i. p. 371. 

 Dcr hintere Beuger dcs UnterschenJcels, WiedemaiiD, p. 96. 

 Der dritte Beiiger des UnterschenJcels, Tiedemaim, p. 335, No. 8. 

 Fl&cMsserir iihial, Meckel, vol. vi. p. 91, No. 3. 

 Pyriformis (?) (part of), Reiil, p. 143. 

 Semi-tendinosus, Owen, p. 37. 

 Semi-tendinosus, Selenka, vol. vi. p. 143, No. 87. 

 Demi-tendineiu; Gervais and Alix, p. 32. 



Attacliments. — This muscle arises from the posterior extremity of the upper (dorsal) 

 border of the ischium, as well as from the transverse processes of the third, fourth, and 

 fifth caudal vertebrae. The fibres pass obliquely downwards and forwards, and are 

 inserted by means of a delicate, flattened tendon into the internal anterior tibial crest, 

 half an inch below the upper end of that bone. 



Action. — It flexes the knee and extends the hip joint. If the knee joint be fixed the 

 posterior fibres of the muscle depress the tail. 



Relations. — The semi-tendinosus lies parallel with the posterior border of the biceps. 

 It rests upon the cruro-coccygeus, and is crossed superficially by the sciatic nerve. Its 

 insertion into the tibia coalesces with, and lies behind that of the semi-membranosus. 



Nerve siq^ply. — A branch of the sciatic nerve, which enters the deeper surface of the 

 muscle. 



Remarks. — As observed by Gervais and Alix in EudyjJtes chrysoloplius, as well as by 

 Meckel, the accessory or femoral head of origin of the semi-tendinosus is entirely absent 

 in every species of Penguin. According to the last named anatomist, the same arrange- 

 ment is met with in the majority of water birds. 



6. Semi-menibranosus. 



Biceps (part of), Vicq d'Azyr, 1774, p. 507, No. 3. 



Der dritte Beuger des Unterschenkels, Wiedemann, p. 97. 



D&r vierte Beuger des Urderschenkels, Tiedemann, p. 335, No. 9. 



Senti-membranettx, Cuvier, vol. i. p. 371. 



Muscle No. 4, Meckel, voL vi. p. 93. 



Semi-meml/ranosus, Owen, p. 37. 



Semi-memhranosus, Selenka, vol. vi. p. 144, No. 88. 



Le droit interne, Gervais and Ali.x, p. 32. 



Attacliments. — This muscle arises by two distinct heads, one from the pubic bone and 

 the other from the aponeurosis of the abdominal muscles. The first, or pubic head, arises 

 from about half an inch of the outer side of the posterior extremity of the os pubis, from 

 the posterior cartilaginous extremity of that bone, and from the adjacent surface of the 



(ZOOL. CHALL. ESP. PART XVIIL' — 1883.) S 15 



