FISHERY BULLETIN VOL 76, NO 3 



200- 



400- 



-600- 



800- 



1000- 



1200 



20 40 60 80 



MANTLE LENGTH, mm 



100 



Figure 38. — Vertical distribution of Sandalops melancholicus. 

 From Young ( 1975d). Symbols as in Figure 1. 



Helicocrarichia heehei Robson 1948 



sively greater depths, although the relationship of 

 size to depth is not very precise. The deepest cap- 

 ture was probably at 1,200 m. Mature specimens 

 were not captured. 



Photosensitive Vesicles (Figure 40A) 



One set of organs is present. Each organ consists 

 of a single small oval vesicle located on the poste- 

 rior surface of the peduncle complex. No screening 

 pigment is present. Very slight, if any, positive 

 allometric increase in the size of the vesicles oc- 

 curs from juveniles to the largest specimens. 



Bathothanma lyromma Chun 1906 



Vertical Distribution (Figure 41) 



Although only 12 specimens were captured, a 

 general pattern of ontogenetic descent is evident. 



Vertical Distribution (Figure 39) 



Including larvae, 47 specimens were captured. 

 Although day and night captures are not well in- 

 termingled in Figure 39 (due largely to sampling 

 inequities), the data indicate that this species does 

 not migrate. Rather, it seems to undergo on- 

 togenetic descent. The youngest specimens were 

 captured between 100 and 200 m. Progressively 

 larger specimens were generally taken at progres- 



FlGURE 40. — A. Photosensitive vesicles of Helicocrarichia 

 beebei. B. Photosensitive vesicles of Bathothauma lyromma. 

 Abbreviations as in Figure 2. 



200- 



400 



6 600 



X 

 a. 



S 800- 



1000- 



1200- 



1400 



"1 1 1- 



I '^ 



—tfi* . • 4 .^i 





« • 



10 20 30 40 50 60 



MANTLE LENGTH, mm 



1200- 



20 



40 60 80 100 



MANTLE LENGTH, mm 



140 



Figure 3.9. — Vertical distribution of Helicocrarichia heehei. 

 Symbols as in Figure 1. 



Figure 41. — Vertical distribution of Bathothauma lyromma. 

 Symbols as in Figure 1. 



604 



