590 MR. F. E. BEDDARD ON THE [Dec. 3, 



Buceros lunatus and B. bicornis, which are hoth large species, 

 hardly present an}' differences from B. rhinoceros. 



Bijcanistes subcylindricus has a syrinx which, although of about 

 the same size as that of Ceratogymna data, shows certain differences 

 which are worth putting on record. In the first place, the syrinx 

 is much compressed from side to side at the level of the last tracheal 

 ring ; in the second place, the last tracheal ring is very much more 

 arched than usual ; it forms indeed almost a complete semicircle. 

 The intrinsic muscle of the syrinx in this, as in the other smaller 

 Hornbills, is very much larger relatively than in the larger species. 



Anthraceros malayanus, again, is a little different from all the types 

 hitherto described. The last tracheal rings are but little fused 

 posteriorlv, only the penultimate and antepenultimate rings are so 

 fused, so that it is impossible to he certain as to the origin of the 

 pessulus. The intrinsic muscles are slender. 



Toccus presents certain peculiarities which I have not yet observed 

 in any other Hornbills ; the trachea has two pairs of extrinsic 

 muscles given off about § an inch apart. This condition seems to 

 me to be so remarkable that I liave preserved the specimen which 

 shows it, though unfortunately the insertions of the anterior pair of 

 muscles are lost and I have no recollection of where the point of 

 insertion was. The intrinsic m.uscles are relatively small. There 

 appears to be no fusion between any of the tracheal rings. 



Myology. 



The arrangement of the semitendinosus and adductor in Aceros 

 nipalensis, which is somewhat complex, will be understood from the 

 accompanying drawing (woodcut, fig. 3, p. 591). 



The semitendinosus (St) is inserted on to the tibia by a long 

 thin flat tendon ; another tendon joining the first just where it 

 passes into the muscle is attached to the gastrocnemius. 



The accessory semitendinosus is in two parts : the larger half 

 {Ast) is attached to the semitendinosus just behind the origin of 

 the tendon of insertion of the latter ; the second half appears 

 to arise from the tendon which connects the semitendinosus with 

 the gastrocnemius, it passes up towards the thigh, and just in front 

 of its (tendinous) insertion on to the femur it receives a tendon 

 from the adductor. This latter muscle (the adductor longus) is 

 inserted by three tendons: — (1) to the femur ; (2) a small tendon 

 which has already been described as joining the second half of the 

 accessory tendinosus ; and (3) near to the origin of one of the internal 

 heads of the gastrocnemius ; to this tendon is also attached the 

 inner head of the gastrocnemius. 



The corresponding muscles' of Bucorvus abyssinicus are rather 

 simpler than in Aceros nipalensis. The adductor longus is only 

 inserted at two places : first by a fleshy insertion along a considerable 

 length of the lower border of the femur ; second by a tendon in 



'^ Gadow figures most of these muscles in Bronn's ' Thierreiehs,' Aves, Bd. vi. 

 Abth. iv. Taf. Yxiii. b. fig. 1, 



