456 
HENRY F. NACHTRIEB 
Figs. 1 and 2. Photographs of the dorsal and ventral surface respectively of a bill 
300 mm. long from the tip of the bill to the eye. The fish was a little more than one 
meter long from the tip of the bill to the tip of the dorsal lobe of the tail. The clus- 
ters of lateral line branches shown in fig. 2 were painted white to make 1hem 
stand out more clearly. As a rule they are inconspicuous. Fig. 2 was inadvert- 
ently photographed on a slightly larger scale than was fig. 1. 
Figs. 3 and 4. Photographs of the two halves of a portion of a bill cleared in 
caustic potash. The black lines represent the sheaths of pigment cells surround- 
ing the blood vessels. The groups of black spots represent the groups of primitive 
pores. In fig. 4 the lines and spots were accentuated with India ink. Fig. 3 has 
not been retouched. 
