108 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



ing power. It may well be that all these fishes 

 originally cast free their ova, and only gradually 

 developed the instinct that now leads them to 

 place it in safe keeping. It may have been a 

 simple accident that caused the ova of the Syngna- 

 thus to adhere to its breast, as that of other fishes, 

 throwing mucus-clad ova, always threatens to do 

 until driven away by the ventrals. 



As it is, we find the young of SyngnatJius acus 

 hatched in the long pouches, whence they can be 

 withdrawn and examined by the observer, who will 

 find that, as was to be expected from unduly coddled 

 young, they are greatly behind other young fishes 

 in taking care of themselves. When a young fish 

 breaks the zona radiata and starts forth on its own 

 account, even with a considerable umbilical sac, it 

 displays an amount of intelligence, and capacity for 

 taking care of itself, far greater than the same fish 

 when matured. This is not the case with the fostered 

 Syiignathus, which, even when all the sac is absorbed, 

 will return to the paternal pouch with the compla- 

 cency of a scapegrace. 



It may be worth noting how the mouth, in the 

 youngest forms in our possession, has the soft, 

 sucking, turned -up lips of a young mammal. In 

 the next stage the lips are more prominent, but 

 still of the same sucking character. This character 

 it continues to display as it advances ; and, dropping 

 all but the smallest approach to jaws, it lengthens 

 its sucking, siphon-like mouth in homogeneity with 

 its lengthening body, and reduces its gills to a 

 puncture anterior to the eyes. The accompanying 

 outlines (Plate I.) will best explain the character 

 of the change that takes place in the mouth as the 

 creature advances towards maturity. 



Here also may be observed the differentiation 

 that takes place in the advancing alevin, which, 

 with quite as much development of external jaws 

 as other less coddled youngsters at the same stage, 

 continues through disuse to allow them to lose their 



