REPRODUCTION— CARE OF THE OFFSPRING 215 



during the whole period of incubation, during which time she is 

 fed by the cock. In the nearly allied Hornbills this peculiar 

 division of labour reaches a very remarkable and unique 

 climax. Among these birds — there are several species — but 

 a single egg is laid, and this is deposited within a hollow tree. 

 Directly afterwards the male proceeds to close up the entrance 

 to the nest, leaving but a narrow slit ; but except for this aper- 

 ture, through which she thrusts her bill to receive the food 

 brought by her indefatigable mate, there is no communication 

 with the outer world. She is a prisoner, we presume volun- 

 tarily, until the egg is hatched ! The substance used in this 

 walling-in operation would seem to differ among different 

 species, varying doubtless according to the materials available 

 in the different parts of the breeding range. Dr. Hose, a keen 

 naturalist, and for many years one of the resident magistrates 

 of Sarawak, carefully examined the plaster used by the Rhin- 

 oceros-hornbill (Buceros rhinocct'os), and found it composed of 

 a substance resembling vegetable resin — probably a salivary 

 secretion — mixed with the woody fragments of fruit. Some 

 species appear to use the undigested skeletons of centipedes 

 in addition. 



During her period of solitary confinement, as we have re- 

 marked, she is assiduously fed by her mate. And thereby 

 hangs a tale, as wonderful as anything in nature — wonderful 

 because her daily rations are passed to her in the form of a 

 bolus, the investing coat being furnished by the inner lining of 

 the gizzard of the male ! At least this is the commonly ac- 

 cepted explanation of the structure of this capsule, though it 

 is probable that it may prove to be formed by a special glandu- 

 lar secretion when the matter is further investigated. This is 

 the more likely interpretation, because, according to other ac- 

 counts, each meal is divided into from two to four pellets — 

 containing fruit, seeds, insects and portions of reptiles— which 

 the devoted cock transfers into the gaping mouth of his fair 

 prisoner by a series of jerks. No wonder that by the time the 

 egg is hatched she has become a " mass of fat," while he is 

 reduced to a mere skeleton, so lowered in vitality that on a 

 sudden fall in the temperature, such as takes place after rain, 

 he not seldom falls down exhausted and dies ! 



Speaking broadly, the hens alone sit among the Game-birds, 



