Opisthoteuthis depressa: Description Continued

1. Eyes
   1. Large, diameter 1/2 head width.
2. Funnel
   1. Funnel organ not described.
3. Fins
   1. Length 1.5-2.0 times width.
4. Gills
   1. Number of gill lamellae not described.
      
      
5. Optic lobe and nerves
   1. Not described.
      
      
6. Digestive tract
   1. Not described.
      
      
7. Beaks
   1. Not described.
      
      
8. Male and female reproductive system
   1. Not described.
      
      
9. Shell
   1. Nearly straight in young, U-shaped in adults.
   2. Saddle with figure 8 cross-section.
   3. Wings tips conical.
   

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   Figure. Shell of O. depressa. A - Posterior view of holotype. B - Posterior view of wing showing cross-section, same shell. C - Dorsal view, adult male. D - Posterior view of wing showing cross-sections, same shell. Drawings from Sasaki, 1929.

10. Pigmentation
    1. Aboral surfaces deep gray.
    2. Oral surfaces mostly reddish violet.
    3. Lips, cirri, margins of suckers and undersurfaces of fins lighter hue.
    4. Areolae - Pink, mostly in 8 rows. Anterior 4 rows each with 8-9 areolae. Rows begin behind eye prominences and extend forward along mid-aboral surface of arms I and II. Posterior 4 rows each with 8-9 areolae. Rows begin behind fins and extend along mid-aboral surface of arms III and IV. Additional areolae: One on upper surface of funnel; 2 on web near fin bases.
    

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    Figure. Aboral view of small (ca. 135 mm max. width) female of O. depressa. Drawing from Sasaki, 1929.

11. Measurements

    Sex	Male	Female
    Head width, mm	38	35
    Fin length	18	15
    Fin width	12	10
    Arm I, length	125	100
    Arm II, length	130	104
    Arm III, length	135	110
    Arm IV, length	132	110
    Max. sucker diameter	9-10	2

Comments

The above description is taken from Sasaki, 1929.

References

Sasaki, M. 1929. A monograph of the dibranchiate cephalopods of the Japanese and adjacent waters. Journal of the College of Agriculture, Hokkaido Imperial University, 20(Supplementary number):1-357.