THE EXTREMITIES OF ORVCTEROPUS CAPENSIS. 59." 



Douglas l mentions the origins of the heads of the ga8tru< <'miua in the dog " Jr 



two ossa sesamoidea that adhere to the two condyles of the femur." 



Krause, in his monograph on the Babbit 1 ', docs not refer to any sesamoid in connexion 

 with the gastrocnemius, but states that the plautark arises from such a bone in th« 

 neighbourhood of the " lateral condyle" of the femur. 



In Meckel's ' Comparative Anatomy ' * a long list is given of animals which have one or 

 more of these bones in the gastrocnemius. On his authority, they occur in both tendons 

 in many Apes, in the Mole, in the Agouti, Porcupine, and other Rodents. ]n Stemops, 

 however, among Quadrumana, and, among Edentata, in the Al and the Anteater, there is 

 but one sesamoid ; but in the latter Order they are larger than in other mammals. Th 





are wanting in the Ormthorhynchu*, among Monotremes, and in Man they are s ldom 



present. 



Dr. Tig, in his monograph on sesamoid bones 4 , mentions the existence of bones of tit 



character in the origins of the gastrocnemius in Cynocephalus sphinx (Simla sphm 



Linn.). Meckel 5 has noted the same in his « Comparative Anatomy' as occurring in tin- 

 species of Ape. 



Burdach 6 , in a paper upon the myology of Lnius, Cyvoccphalus ; and Cercopithecut 



(species not given), mentions the existence of such a bone at the outer as well as the 

 inner condyle of the femur, in the origins of the gastrocnemius in these Apes. 



Man is not exempt from the presence of such bones in the gastrocnemius; for, accord- 

 ing to Soemmering 7 , " non raro tendo ventris extcrni os sesamoides excipit." The same 

 anatomist remarks, after citing an author who had found two bones of this description, 

 " forsan vero alterum fuit ossiculum, quod passim in bursis mucosis invenitur." 



Henle, too, mentions the occasional occurrence of sesamoid bones in Man", in tin 

 lateral and, more rarely, in the middle head {soleus) of the gastrocnemius, but regards 

 them as pathological ossifications, such as are caused in other muscles by friction, e. g. 

 in the median portion of the vastus in riders— a point which Fordhani or Custauce ma\ 



some day have the privilege of illustrating. 



In the fine skeleton of the Megatherium, preserved in the Museum of the lioyal 

 College of Surgeons, there is a sesamoid bone behind the outer condyle of the left femur. 

 In all probability this was once imbedded in the gastrocnemius of this huge species of 



Sloth. 



So l eus —A flat and comparatively broad muscle, taking origin by a distinct tendon, 



imbedded in the origin of the deep flexor, from a sharp tubercle on the posterior aspect 



of the head of the fibula, and being inserted into the superior and inner face of the 



calcaneum. ■ 



Prof. Humphry makes no mention of this muscle by name. He may, however, With 



the old anatomists, have described it as an element of the gastrocnemius, in which case 

 it will answer to his description of the third head of origin of this latter muscle ». 



1 Myographiaj Comparatae Specimen (London, 1 707), p. 154. 



Anatomic 



Loc. cit. p. i >4. 



Abtheilung 



4 Monograpnie uer otuncmuni-n, »ivw«« •* w *«— -«i o v , 



5 7 't 634 e Beitrag TOT vergleichenden Anatomic des Affen (K nigsberg, 1838), p. 47. 



7 De Corp. Hum. Fabr. (Trajecti ad Moenum, 1796), tome iii. p. 300. 



Muskellekre 



• Loc. cit. p. 313. 



