218 



STRUCTURE AND CLASSIFICATION OF BIRDS 



from both the types already described, although the resem- 

 blances are on the whole closer to Aceros. 



The adductor longus is attached by two tendinous heads ; 

 the upper one of these, as in Aceros, is attached to the lower 

 border of the femur ; this corresponds to the fleshy insertion 

 of the muscle in Bucorvus ; the lower tendon is fused on its 

 way with the inner head of the gastrocnemius, which is 

 continued upwards and reaches the femur, and then bifur- 

 cates into two tendons of insertion. The relations of the 



rtMl 



Fig. 101. — Leg Muscles of Aceros (afteb Beddaed). 



add, adductor ; St, semitendinosus ; Ast, its accessory ; Sm, semimembranosus ; 

 gmt, gastrocnemius. 



semitendinosus and of the accessory semitendinosus are as 

 in Aceros nipalensis. 



In Toccus these muscles are much the same as in 

 Buceros. 



In Geratogymna elata I find a closer resemblance to 

 Aceros than to any other of the genera mentioned in this 

 paper, but there is an agreement with Bucorvus in the fleshy 

 insertion of the adductor longus on to the lower border of 

 the femur. The accessory semitendinosus is distinctly double, 

 as in Aceros, and is attached by a short tendon to the 



