ANATOMY OF GRUIFORM BIRDS. 4-17 



forked at the extreme distal end. The peculiar accessory head of 

 the biceps, first noted by Beddard (P. Z. S. 1891, p. 14) and 

 confirmed by myself (P. Z. S. 1901, p. 639) from dissection of 

 another example of Rhinochetus, was doubtfully represented in 

 the present example, an old and excessively fat bird, by a lump 

 of fat and fibrous tissue- 



Ilio-tibialis internus {sartorius), — As in other Gruiform birds, 

 rather easily separable from the ghitseus maximus, 



lUo-tibialis (glutceus maximus). — Tins large muscle, with rather 

 weak median and very strong post-acetabular portions, had the 

 disposition found in Gruiform birds generally, 



Ilio-trochanterici posterior, anterior, and medius, were all 

 distinct and well developed as in other Gruiform birds, but the 

 small median muscle {glutceus qtcartus) was absent in ^4, giganteus 

 as in A. scolo^Jaceus ; in the present example of Rhinochetus it 

 was just sepai'able. 



Caibd-ilio-femoralis {femoro- caudal and accessory). — The femoro- 

 caudal was absent in A. giganteus as in ui. scolopaceus, present 

 but small in Rhinochetus ; the accessory wa« large, but with an 

 area of tendinous degeneration in A. giganteus, precisely as in 

 A. scolopaceus, absent in Rhinochetus. 



Ambiens. — Present in both A. giganteus and Rhinochetus, its 

 slender tendon, after passing round the knee, i-eceiving a strong 

 anchor from the head of the fibula. 



Caud-ilio-f,exorius{seinitendinostis s,n(}i accessory semitendinosus). 

 Ischio-Jlexorius {semimemhranosus). Gastrocnemius, middle, or 

 posterior femoral head. — For convenience, to explain the in- 

 teresting relations of this group of muscles, I have repeated here, 

 as text-figures 1-4, the text-figures 81-84 in my paper on 

 Gruiform birds already published in the Proceedings of this 

 Society (P. Z. S. 190i, pp. 650-651). In A. giganteus, as in 

 A. scolopaceus (text-fig. 2), the semitendinosus (C.I.L. 2) is wide, 

 but not so large as the semimembranosus (I-F.), except -^owards 

 its insertion, whereas in Rhinochetus it is enormous, much 

 larger than the semimembranosus. In A. giganteus the accessory 

 semitend. (C.I.L. 2) is a broad triangular muscle, meeting the 

 semitend. in an oblique raphe, exactly as in A- scolopaceus (text- 

 fig. 2), and then running down to joiri the middle head of the 

 gastrocnemius, which it covers ; the semimembr., also as repre- 

 sented in that figure, sends a slip to the conjoined semi- 

 tendinosus and accessory semitend., and passes on to the tibia 

 by a flat ligament (A, 2). There was also a thin flat ligament 

 from the semitend. raphe to the tibia, which I did not find in 

 A. scolopaceus, but which I found in Rallus (text-fig. 1, A. 1). 



The condition of this group of muscles in the example of 

 Rhinochetus that I am now describing, corresponded, except in 

 one importaiit respect, with what I found on a former occasion 

 and described as resembling the condition in Otis (text-fig. 3). 

 The semitendinosiis, accessory semitend., and semimembranosus 

 unite to form a flat tendon of insertion to the tibip, (A. 2) plainly 



