420 DR. p. CHALMERS MITCHELL OX THE 



corresponds with Gadow's second gi'oup, except that there is, in 

 addition, a second distinct middle gastrocnemius. 



Gastrocnemius, external femoral head, and internal tibial head. 

 Ilio -fibular is {biceps, with sling and anchor). Soleus. — All these 

 presented no peculiai'ity, and were similar in the two species of 

 Aramus and in Rhinochetus. 



Pub-ischio-femorales (adductors). — I]i all three birds both were 

 present, without trace of tendinous degeneration, and, as in most 

 Gruiform birds, the internal muscle was much stronger and wider 

 than the external muscle. 



Ischio-femoralis (pbdurator externum), ohdurator (obdarator 

 internus) ; accessorii obduratot^is. — With regard to these muscles, 

 I have to note only tliat the obdurator externus was notably 

 small in A. giganteus, and that the area of insertion, to the shape 

 of which Garrod attached importance, was markedly triangular 

 in that bird, as in ^. scoloj^aceus and in Rails and Cranes. It is 

 much more oval in Rhinochetns. 



Peroneus suj^erficialis ivnA 2yeronei(,s 2Jrofundus. — In both species 

 of Aramus &nd in lihinoclietus the superficial muscle is the more 

 important, with a broad superficial origin, extensive origin from 

 the fascia of the adjacent muscles and, in Aramus, almost no deep 

 origin, but a cei'tain amount of it in Rhinochetus. The anchor 

 to the sustentaculum of the flexor tendons is broad in all three 

 and shows traces of being broken into separate slips.. The 

 tendinous slip to the flexor of the third digit is well developed in 

 all thi'ee bii-ds. The deep muscle is very strong in RhinocheUis, 

 arising from a large part of the fibula, beginning at the insertion 

 of the biceps tendon, and from the adjacent surface of the tibia. 

 It passes in the normal fashion into a flattened tendon running 

 in a groove under the slip to digit III of the superficial muscle. 

 In A. SGolopdceus I did not find it, but in A. giganteus it was 

 represented by a very minute muscular head arising high up from 

 the fibula opposite the biceps insei"tion, and passing at once into 

 a most slender ossified tendon, so closely adlierent to the fibula 

 that, unless it weie specially searched for, it might easily be missed. 

 It has the usual insertion by a. very thin flattened tendon in a 

 groove under tlie slip to III. The tendons of both peroneals were 

 ossified in Aramus, as in many other Gruiform and Limicoline 

 birds, biit in Rhinochetus there was no trace of ossification. I have 

 shown, in a former communication to the Society (" The Peroneal 

 Muscles in Birds," P. Z. S, 1913), that in Gruiform birds there 

 is a tendency for the deep peroneal to become reduced or to dis- 

 appear, 60 that it would not be remarkable to find it present in^ 

 A. giganteus and absent in A. .scolopaceus, even if these forms 

 were not speeifica,lly distinct. 



Tibialis anticus ; Exteofisor digitorum communis ; Flexores per- 

 forantes et 2ierfora,ti of digits II and III. — These muscles ai'e all 

 ]3resent in both sjDecie^ of Aramus and in RhinochetxLS and have 

 the disposition that is normal in birds generally. The most 

 notable point of difierence is that in Ai-amus the tendons are all 



