A/rn<5P-R ,nA AHTSTROM: DEVELOPMENT OF SCOPELOPSIS MULTIPUNCTATUS 



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Figure 12. — Developmental stages of Gyimwscopelus aphya Giinther. — A, 23.5-nim larva, U.S. NS Eltanin Sta- 

 tion 319; B, 23.5-mm larva, dorsal view; C, 27.7-mm transformation stage, U.S. NS Eltanin Station 1341. 



ing its upward migration, one might expect a 

 comparable deletion or modification at its origin 

 in the ventral scale row. There is none. An- 

 other major deficiency in the theory is its ina- 

 bility to explain the photophore pattern of a spe- 

 cies such as Notolychnns valdiviae which has 

 four pairs of photophores near the dorsal mid- 

 line. If derived from the ventral series, the 

 dorsal photophores would be supplied by periph- 

 eral nerves of the ventral or medial spinal rami 

 that would have to extend dorsad across the hor- 

 izontal septum; such an arrangement seemed so 

 unlikely for species with photophores above the 

 lateral line that we traced the nerve supply to 

 such photophores in Triphotunis mexicanus, 

 Bolinichthys sp., and Notolynchmts valdiviae. In 

 T. mexicanus the VLO, SAO.-s, POL2, and Prcs 



lie above the lateral line, and in Bolinichthys the 

 latter three photophores lie above the line. These 

 light organs are supplied by a branch of the lat- 

 eral vagus nerve, the superficial lateral-line 

 nerve. In Notolychnns the VLO, SAO3, POL2 

 and Prc2 lie extremely high on the body near the 

 dorsal midline. The VLO and SAO3 are supplied 

 by the dorsal ramus of the lateral vagus nerve. 

 The nerve supply to the POL2 was difficult to 

 determine but appeared also to be the dorsal 

 ramus of the lateral vagus nerve. The Prco is 

 innervated by the superficial lateral-line nerve. 

 Ray (1950), in her detailed study of the per- 

 ipheral nervous system of Stenobrachius leucop- 

 sarns, showed that all body photophores, except 

 three pairs, are supplied by ventral rami of spin- 

 al nerves. The exceptions, SAO3, POL, and Prc4, 



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