520 PARENTAL CARE AMONG FRESH-WATER FISHES. 



these tisli showed indications of carrying ova in its mouth. Tlie gill covers did 

 not fit closely over the cavity containing the gills, but were distended, making 

 the fish look as though it had a swollen head. This fish I removed into 

 another " tank," of which it became the sole occupant. This little fish meas- 

 ured two inches and three-quarters in length including the tail. The tank in 

 which I kept it for observation was a small aquarium measuring eight inches by 

 five, with a depth of water of two and a half inches. A few roots of ValUsneria 

 spiralis provided the necessary oxidation of the water. A few days after the fish 

 was introduced into this " tank " the swelling out of the gill-covers became mofe 

 marked, until they stood out or remained oi)oned quite a distance from the cavity 

 of the gills. Beyond this feature nothing particular was to be noticed for some 

 days. But after these days a very interesting stage in the development took 

 place. I was enabled to see that the ova had evidently matured, for I could see 

 a number of tiny living forms moving about in the mouth of the parent fish. A 

 slight development also took place beneath the lower jaw of the fish in the shape 

 of an expansion of the membrane, which made more room in the mouth and re- 

 minded one somewhat of the dilatable pouch affixed to the lower mandible of a 

 pelican. This pouch being partly transparent, as well as a portion of the head 

 near to it, I was enabled to see fairly well right into the mouth cavity. 



For some minutes nothing could be observed in watching the head of the 

 fish but the rhythmic movement of the low'er jaw and gills ; but after an in- 

 terval I could clearly see all the young fish in a great state of commotion, 

 filling the whole front of the mouth with a living pack of minute dark creatures 

 whose movements reminded one of the ways of tadpoles when huddled together 

 in dense masses, only with this difference, these tiny fish moved with great 

 rapidity. After these creatures had made one of their periodic excursions to 

 the front of their parent's mouth they always retreated out of sight to the back, 

 and nothing more would be seen of them for a few minutes, and then there 

 would be another turmoil and mad rush to the front ; but none of them ever 

 escaped out oT the mouth. I think that these movements might be accounted 

 for on the supitosition that as these embryonic fish began to grow the.v gave 

 the parent fish some inconvenience, and that owing to this the fish was obliged 

 to constantl.v force his growing family from the pharynx to the front of the 

 mouth, giving [her] an opportunity of relieving [herselfj from the choking 

 feeling [she] nnist have been constantly subjected to. These little fish did not 

 swim to the front of the mouth, but were evidently rushed there, as they looked 

 like a ball composed of a great number of minute wriggling creatures whose 

 real shape could not be seen because of the rapidity of their motion, which 

 was more a revolving motion than any other. I could not see well enough to 

 observe whether they were really fish-like in form or embryonic, and I did 

 not like to disturb the fish enough to find out. I simply kept close watch 

 day after day. These movements continued for some days, during which time 

 I allowed several of my friends to come to my study and witness the strange 

 sight, which was regularly repeated every few minutes. 



After two weeks had passed these movements almost ceased for a time, 

 and I had fears that all was not going well ; but after careful watch for a few 

 more days I entered my study early one morning, and to my great delight saw 

 a large number of little fish, very perfect and beautiful, slowly and gracefully 

 ?winuning about near to their parent's head, their movements now being very 

 different from the wriggling, hurry skurry which marked their movements prior 

 to their leaving for the first time their i)arent's mouth. I tried to count the 

 number (jf young in this shoal so strangely brought into the world, i counted 

 sixty for certain, but there were probably two or three more. And now, being 



