EEPORT ON THE SPHENISCTD.^. 127 



terminal phalanx and gives off lateral bands to the base of each of the proximal phal- 

 anges of that toe as it passes to its insertion. 



Action. — The muscle extends the toes. 



Relations. — The muscle rests against the front of the tibia, and is concealed by the 

 tibialis anticus. 



Nerve supply. — A branch from the anterior tibial nerve, given off so soon as that 

 nerve reaches the front of the leg. 



Variations. — In all the species of Penguin dissected, with the exception of Eudyptes 

 chrysocoine from Tristan d'Acunha, and Spheniscus demersus, the tendon of the 

 extensor digitorum divides into three instead of into four slips. In these, therefore, 

 the thii'd toe is provided with a single tendon, instead of two, as above described. In 

 Spheniscus demersus the distribution of the tendons exactly resembles that which 

 obtains in Eiidyptes chrysocome from Tristan d'Acunha. 



Remarks. — According to Meckel, in the Penguin the tendon of the extensor com- 

 munis divides as described above in Eudyptes chrysocome from Tristan d'Acunha. 



The annular ligaments beneath which the tendon of the extensor digitorum passes 

 are two in number. The upper is attached to the lower end of the tibia, and is oblique 

 from above downwards and outwards. Its inner end is fixed to a ridge immediately 

 above the internal condyle of the lower extremity of the tibia, whilst its outer end is 

 attached to the front of the external condyle. Beneath this ligament pass the tendons 

 of the tiliiaUs anticus and extensor digitorum. The lower ligament is attached to the 

 upper end of the second metatarsal bone. Through it passes the tendon of the extensor 

 digitorum alone. 



1 1 . Extensor hrevis hallucis. 



L'ahdudeur du doigt oppose, Vicq d'Azyr, 1774, p. 516, No. 1. 



Der Daumenstrecker, Wiedemann, p. 106. 



Der Strecker des Daumens, Tiedemann, p. 345, No. 8. 



Muscle No. 2, Meckel, vol. vi. p. 109. 



L'extenseur du poiLce, Cuvier, vol. i. p. 393. 



Extensor pollicis hrevis, Owen, p. 40. 



Extensor of the thuinb, Eeid, p. 145. 



Extenseur du pouce, Gervais and Alix, p. 38. 



Attachments. — The short extensor of the hallux is a very delicate muscle. It aiises 

 from the metatarsal bone of the first or rudimental toe, as well as from the ligament 

 which connects the first to the second metatarsal bone. Its tendon passes along the 

 dorsum of the first metacarpal bone, and is inserted into the base of the first phalanx of 

 the haUux. 



Action. — It extends the toe. 



Nerve supply (?) 



Remarks. — Meckel notes the occurrence of this muscle in the Penguin. According 



