PSITTAOI 261 



absent from the Psittaci. This is certainly almost univer- 

 sally the case. But Furbringer speaks of a rudiment — a" 

 short length of tendon — in Platycercus paUiceps. 



No parrot has a biceps slip. A muscular cucullaris 

 patagialis is generally, if not always, present. 



It is well known that the ambiens muscle is present in 

 some parrots, and absent from the leg of others. The actual 

 occurrences of this muscle are shown in table (p. 268) . Strin- 

 gops is peculiar in that the muscle is sometimes complete 

 and quite normally developed, and sometimes ends in a thin 

 tendon on the capsule of the knee joint. This recalls 

 (Edicnemus. 



Of the other muscles of the leg used by Garrod in classi- 

 fication A, X, and Y are nearly always present, the only 

 exception, so far as I am aware, being Chrysotis Guildingi, in 

 a specimen of which I failed to find Y. 



Sometimes (as in Ara cMoroptera) the semitendinosus 

 gives off a tendinous slip to the gastrocnemius, but in 

 Chrysotis there is no such slip. The tibialis anticus is 

 usually inserted by a single tendon. This Mr. Parsons and 

 I found to be the case in the majority of parrots which we 

 examined. But in Chrysotis the tendon is distinctly double. 

 In Deroptyus, Caica, Paeocephalus, Platycercus, and a few 

 others, there are more or less evident indications of a double 

 tendon. 



The deep flexor tendons of the parrots are gallinaceous, 

 with a vinculum such as is illustrated in fig. 54 (p. 100). 

 There are some inconsiderable variations of this ground plan ; 

 for instance, in Platycercus Barnardi the vinculimi is divided 

 into two parts, one to digit II., the other to III. and IV. 



Peroneals. — The peroneus longus and brevis are, as far as 

 we have observed, always present in parrots, but the origin 

 of the former differs somewhat in different genera. 



In Stringops and Nestor the peroneus longus rises from 

 the front of the bony fibula and its membranous continuation 

 for about the upper half of the leg. The muscular belly 

 overlaps that of. the peroneus brevis very much near its 

 origin, and the muscle is large and well marked. 



