ENGYSTOMATINAE 229 



dorsalwards around the flanks, almost to the vertebral dia- 

 pophyses ; ventrally and forwards it reaches the chin. The walls 

 of the sac are of the same structure as the buccal lining, of which 

 they are in fact continuations. They adhere, at intervals, to the 

 cutis and to the pectoral and abdominal muscles. 



The effect of the distension of the sac upon neighbouring 

 organs is twofold. First, the viscera are pressed back within the 

 abdomen ; this disturbance is temporary and does not apply to all 

 specimens ; the feeding in no way impeded. Secondly, a per- 

 manent change is produced in the direction of the precoracoid 

 bars, in such a way that each bar is curved tailwards and rests 

 with its ventral half upon the coracoid ; owing to this forcible 

 bending the clavicles do not meet each other. There is, of course, 

 not so much space gained by this slight rearrangement of the 

 shoulder -girdle as Espada implies, but we have here, perhaps, 

 an illustration of direct correlation between two originally 

 independent organs, namely, shoulder-girdle and vocal sacs. Ee- 

 peated distension of the throat-bag during every breeding season, 

 while the whole organisation of the male is in a highly excitable 

 condition, has pressed the clavicular bars back, or rather has 

 staved them in, and this at first pathological and abnormal con- 

 dition has at last become a fixed feature. It is to be regretted 

 that we know next to nothing about the habits, especially the 

 mode of breeding, of the other genera which likewise have reflected 

 or very feeble precoracoids and clavicles. Their weakness or even 

 complete absence must have a reason, or rather must have had 

 a cause. 



The pairing and oviposition, and the manner in which the 

 eggs are conveyed into the gular sac, have not yet been observed. 

 Espada examined five males with young, the number of which 

 varied from five to fifteen. In one male with eleven embryos the 

 most developed tadpoles measured 13 '5 mm. from the snout to 

 the end of the tail, and they were lying within the chest of the 

 father, the less advanced in the farther recesses of the bag. Three 

 of the tadpoles had already completely-formed fore- and hind-limbs, 

 while the arms were still hidden. The least developed were still 

 globular, a proof that the eggs are conveyed into the bag. 

 Another male with fifteen embryos looked as if it had gorged 

 itself with the almost fully -formed tadpoles, which measured 

 14 mm. They were quite irregularly distributed, and nowhere 



