310 H. H. NEWMAN. 



of the male slip in under the homologous fins of the female, which 

 are raised up to admit them, and nearly surround the body of his 

 mate. The ventral fins of adjacent sides are also locked in simi- 

 lar fashion. The female is usually forced against some perpen- 

 dicular solid object such as a stone, a mass of seaweed or the 

 glass sides of the aquarium --most frequently the latter when in 

 captivity. When the female is thus seized by a male she sud- 

 denly assumes a characteristic attitude, the whole body, when 

 observed from above having the conformation of a somewhat 

 flattened S, the head being pressed against the solid, that part 



/ 



TEXT PLATE I. Showing the spawning attitude of male and female Fundulus 

 heteroclitus, the female darkened. 



FIG. i. Ventral view, showing the position of anal and ventral fins. 



FIG. 2. Dorsal view, showing the position of dorsal fins. This view is a half 

 side view. The straight line indicates the points of contact with a solid substance 

 such as the glass sides of the aquarium. y z natural size. 



of the body just back of the head being bowed outwards and 

 not touching the solid surface, the region of the abdomen 

 being again against the solid, and finally the whole tail region 

 being free from the solid and bent sharply away from it and 

 slightly upwards (see Text Plate I.). In this rigid position she 

 is supported from the bottom by means of her anal fin, which 



