THE BLIND-FISHES. II9 



The details of the embryology are now under consideration. 

 Emphasis need be laid only on the fact that Amblyopsis is not 

 viviparous, and that the breeding period extends at least from 

 the first of March to November, and probably throughout the 

 year. A female with nearly ripe eggs was secured on Septem- 

 ber 9, and since these would have been carried, either as eggs 

 or young, for about two months longer, November is a safe 

 limit. Between November and March but one trip has been 

 made to the caves, and this does not permit of a final settle- 

 ment as to whether or not breeding is carried on at this 

 time. 



Certain structures gain an entirely new significance in the 

 light of the breeding habits. These are the enlarged gill cavi- 

 ties, with the small gills, the closely applied branchiostegal 

 membrane, and the position of the anus and sexual orifices. 

 The latter are placed just behind the gill membrane, in such 

 close proximity to it that they can be covered by it. It is 

 probable, therefore, that the membrane is drawn over the 

 sexual orifice and the eggs deposited directly into the gill 

 cavity. In an individual 35 mm. long the anus is situated 

 between the origin of the pectorals ; in one 25 mm. long it lies 

 between the pectorals and ventrals. In the young it lies 

 behind the ventrals, as in other fishes. 



In an aquarium containing six Amblyopsis two took a great 

 antipathy to each other and engaged in frequent contests. 

 Whenever they came in contact a vigorous contest began. 

 Frequently they came to have a position with broadside to 

 broadside, their heads pointing in opposite directions. At such 

 a time the fight consists in quick lateral thrusts toward the 

 antasconist to seize him with the mouth. The motion is 

 instantly parried by a similar move by the antagonist. This 

 blind punching may be kept up for a few seconds, when by 

 their vigorous motions they lose each other and jerk themselves 

 through the water from side to side, apparently hunting for 

 each other. At this time they are very agile and move with 

 precision. When the belligerents meet one above the other, 

 the snapping and punching are of a different order. While jerk- 

 ing through the water immediately after a round, if one of the 



