No. 3.] PHOSPHORESCENT ORGANS. 673 



the gastric row, curves upward around its posterior end, and 

 terminates in close relation to the pleural row of sense organs 

 (see PI. XXXVIII, Fig. i). There are fifty organs in the 

 entire row. 



The "scapular" row, sc, begins just back of the posterior 

 pore of the temporal canal, runs straight back above the pec- 

 toral fin, then curves in toward the base of the dorsal fin, where 

 it is continued into the dorsal row at the base of the third 

 dorsal ray. There are seventeen sense organs in this row, with 

 an average of ten phosphorescent organs alternating with them. 



The straight part of the scapular row is accompanied by a 

 scapular accessory row, sc ac, of three to five sense organs, with 

 a small phosphorescent organ above each. 



The dorsal row, d, extends along the dorsal surface of the 

 body at the base of the dorsal fin from the third dorsal ray to 

 the caudal peduncle. This row contains an average of seventy- 

 one sense organs. Rarely phosphorescent organs are found 

 between the first three or four organs of the row, but in such 

 exceptional specimens they are always small and rudimentary. 



Outside the dorsal row is an irregular line, or accessory row, 

 d ac, which contains sense organs and rudimentary phosphores- 

 cent organs arranged as in the lateral line. The number of 

 organs in this row is quite variable, an average of sixteen in 

 five specimens (see Table). 



2. Organs of the Lozver Jaiv and Head. 



The branchiostegal row, br, begins in front of the isthmus 

 and extends outward over the membrane of the gill-cover to the 

 base of the lower branchiostegal ray ; then along the membrane 

 between the first and second rays almost to the edge of the 

 gill-cover. There are thirty-four phosphorescent organs in this 

 line and no sense organs. 



The " mandibular " row, md, of phosphorescent organs ex- 

 tends around the inner rim of the ridge formed by the dentary 

 bones. It contains twenty-two organs on either side. 



The operculo-mandibular row consists of surface organs and 

 canal organs. It begins on the side of the head at the anterior 

 pore of the temporal canal. It runs downward on the surface 



