ANATOMY OF GRUIFORM BIRDS. 421 



ossified, above and below the ankle, and are unossified in Rhino- 

 chetus. The flexor tendon of digit III is connected with the 

 perforated flexor tendon of the same digit by a strong slip. 



Flexores perfoixiti, of digits II, III, IV. — In all three birds, 

 as in Gruiform birds generally, there are three heads for this 

 group of muscles, and fibres from each of the three tendons can 

 be traced to each of the three heads. The ambiens head is the 

 tendon of the ambiens muscle, which passes under the biceps 

 ligament, that is to say, between it and the fibula. The fibidar 

 or external head arises by a tendon from the fibula, proximal to 

 the insertion of the biceps and passing superficially to the biceps 

 tendon. The deep or femoral head is fleshy fiom between the 

 condyles of the femur. 



Flexor longis huUucis. — In all three birds this arises by a 

 single head from between the condyles of the femur. 



Flexor j)r of undtis. — Arises from the shaft of the tibia close under 

 the fibula. In Aramus the tendons of the deep flexors are nearly 

 equal in size ; in Rhinochetus the tendon of the longus hallucis is 

 relatively smaller. In A. giganteus the relations between tiie two 

 deep tendons are much as I represented in A. scolopaceus {F . Z. S. 

 1901, p. 654), except that the vinculum to the other deep flexor 

 is spread over the branches to the digits rather more, as in the 

 figure of Exirypyga given on the same page. The present example 

 of Rhinochetus was exactly similar in this respect to the flgure 

 I have given, also on the same page. 



The muscular anatomy affords small ground for separating 

 A. giganteus from A. scolopaceus. The most notable differences 

 relate to muscles that are degenerate in the group, and that 

 might even vary individually — such as the presence of a teres 

 minor in A. scolopaceus which is absent in A. giganteus, and the 

 presence of a pei'oneus profundus in the latter species and its 

 absence in the former. 



The muscular arrangements in which the two species of Aramus 

 agree and differ from Cranes are more numerous, and are in con- 

 formity with the separation of a sub-family Aramina^. 



Osteology. 



I have noted only a few osteological points, the s^'stematic 

 value of which I do not propose to discuss. 



Like that of A. scolopaceus, the skull of A. giganteus is strongl}^ 

 schizorhinal ; the lacrimals are not fused with the skull as occurs 

 in Rhi?iochetus and Limicoline birds. The palate is widely 

 schizognathous with a long pointed vomer, and the pterygoids 

 are short, and expanded anteriorly as in Grus. Ako, as in Grus, 

 there is a pair of occipital foi-amina, and strong descending ex- 

 occipital processes, both absent in Rhinochettts. The skulls of 

 both species of Aramus are exceedingly like those of true Cranes, 

 the likeness extending not only to the larger charaoteivs that have 



