1889. | ANATOMY OF PICARIAN BIRDS. 591 
common with the innermost head of the gastrocnemius. The semi- 
tendinosus is attached by a thin tendon to the tibia as in Aceros and 
by a short tendon, also as in that species, to the gastrocnemius. The 
accessory semitendinosus arises chiefly from this latter tendon, but 
there is no division between this part of the muscle and that which 
takes its origin from the fleshy part of the semitendinosus. 
Fig. 3. 
Leg-muscles of Aceros nipalensis, 
add, Adductor longus; Ast, accessory semitendinosus; S¢, semitendinosus ; 
gast, gastrocnemius ; Sm, semimembranosus. 
In Buceros atratus there is again some little difference from both 
the types already described, although the resemblances 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 bifurcates into two tendons of insertion. The 
relations of the semitendinosus and of the accessory semitendinosus 
are as in Aceros nipalensis. 
In Toceus these muscles are much the same as in Buceros. 
In Ceratogymna elata I find a closer resemblance to Aceros than 
to any other of the genera mentioned in this paper, but there is an 
