SPHENISCI 397 



The penguins have a continuous feathering, the feathers 

 acquiring upon the p'addle-Hke wing a scaly aspect ; ' they 

 have an aftershaft. The oil gland is tufted. 



In the myology of the fore Hmb the most remarkable 

 fact is the entire absence of the biceps, a muscle which is 

 wanting nowhere else among birds. There are also absent 

 the expansor secundarioruni, scapulo-humeralis anterior, and 

 serratus metapatagialis. The tensor patagii longus is pre- 

 sent, and its tendon is inserted on to the whole length of the 

 bones of the arm as far as the extremity of the last phalanx. 

 The latissimus dorsi is peculiar in that its two parts, ending 

 in thin tendons, pass side by side through a pulley arising 

 from the scapula. The pectoralis major (of E. chrysocome) 

 meets its fellow in the middle line over the carina sterni, as 

 in tinamous, &c. In the hind limb the muscle formula is 

 ABX + . The semimembranosus is remarkable for the fact 

 that it has, besides the usual head of origin, a second from 

 the aponeurosis of the abdominal muscles. The accessory 

 femorocaudal (in E. chrysocome) sends a muscular slip to the 

 tendon of the femorocaudal. The tibialis anticus divides in 

 Spheniscus mendiculus into two heads of insertion ; in other 

 species its insertion, as is usual with birds, is single. There 

 is but one peroneus present, the longus. The deep flexors 

 are as in birds with but three well-developed toes, i.e. they 

 blend. In S. demersus there is a slip to the hallux ; in 

 Pygosceles papua, as in Heliornis, the flexor hallucis splits 

 into three tendons, one for each branch of flexor profundus, 

 there being no slip to hallux. The glutseus maximus is 

 absent in Eudyptes, limited in extent in the other genera. 

 The ambiens grooves the patella. 



In the vascular system the most remarkable fact is the 

 breaking up of the brachial artery into a rete in the arm. 

 There are two carotids, which do not fuse. In the leg the 

 sciatic artery is practically absent. 



' It is stated that when moulting the scale-like feathers of the wing are 

 detached in a continuous piece, as with reptiles (Baktlett, P Z. S. 1879, 

 p. 6). 



