126 THE VOYAGE OF H.M.S. CHALLENGER, 



Remarks. — Gervais and Alix describe this muscle in Eudyptes chrysolophus as being 

 attached to the middle plantar tuberosity of the metatarsus, and to the base of the first 

 phalanx of the hallux. Eeid also refers to the presence of a flexor brevis hallucis in 

 Aptenodytes. On the other hand, Meckel (vol. vi. p. 127) asserts the absence of this 

 muscle in the Penguin. My own observations agree with those of Meckel, inasmuch as 

 I have failed to recognise this muscle in any species of Penguin which I have examined. 

 It is right, however, to state that the mode of preservation, and the consequent hardening 

 of the feet of the Challenger specimens, rendered it not a little difiicult to isolate the 

 smaller muscles from the surrounding tissue. In view, therefore, of the recognition of 

 this muscle in two different species by sej^arate observers, and bearing in mind the re- 

 markable similarity in structure otherwise of the various species of Penguin, it seems not 

 improbable that fiirther research will corroborate the observations of Reid and Gervais, 

 and affirm the existence of this muscle in every species of Penguin. 



10. Extensor comrminis digitornm. 



L'extenseur commun des doigts, Vicq d'Azyr, 1774, p. 511, Xo. 3. 



Der geineinschaftliche Fingwstrecker, Wiedemann, ]). 100. 



Der Schienhrin-Muslid, Merrem. 



Der gemeinsehaftliche Fingerstrecker, Tiedemann, p. 340, No. 1. 



Long extcnseur des doigts anterieurs, Cuvier, vol. i. p. 392. 



Long extenseur commun des wteils, Meckel, vol. vi. p. 107, No. 1. 



Described hy Eeid, p. 145. 



Extensor longus digitorum, Owen, p. 40. 



L'extenseur commun des doigts, Gervais and Alix, p. 33. 



Attachments.- — The extensor communis digitorum arises from the lower border of 

 the patella, from the deep groove on the front of the upper end of the tibia between 

 the tibial crests, from the upper half of the anterior internal border of the tibia, and 

 from a strong intermuscular septum which separates this muscle from the anterior head 

 of the gastrocnemius. The muscle terminates on a single tendon which passes along 

 with that of the ti^jialis anticus beneath the anterior annular ligament, and thereafter 

 through an osseous canal situated at the lower end of the tibia. Below that bone the 

 tendon passes beneath a second annular ligament attached to the second metacarpal 

 bone, and forms a flattened expansion which divides into four distinct slips. Of these 

 slips the second toe receives one, the third two, and the fourth one. The tendon to the 

 second toe gives off two lateral bands, which are inserted into the base of the second 

 phalanx, and thereafter passes to be attached to the terminal phalanx. Of the two ten- 

 dons supplied to the third toe, one is inserted into the base of the second phalanx, while 

 the other, after giving off lateral bands to the base of each of the succeeding, is inserted 

 into the last phalanx. The tendon supplied to the fourth toe is inserted into the 



