HoTLE. — Cephalopoda. 



PLATE 9. 



Pterygioteuthis giardi. 



1. Ventral aspect of the animal, after the mantle-cavity has been opened, showing 



the position of the luminous organs ; X 5. 



S., S., Siphoiial organs; B., B., Branchial organs; A^, J.'^, Abdominal 

 organs. 



2. Axial section of one of the larger ocular organs ; X 77. 



a. c, anterior cap; a. co., axial cone ; c, capsule ; c. s., central scales; i". c, 

 inner cone; n., nerve; p. c, posterior cup; s. k., spheroidal knob. 



3. Section through several scales from the inner layers of the posterior cup; 



X 420. 



4. Surface view of two scales from the posterior cup ; X 125. 



»i., nerve. 



5. View of the right siphonal organ ; X 10. 



6. Section of a siphonal organ ; X 88. 



a. c, posterior layer ; and a. c,^, anterior layer of anterior cap ; c, capsule ; 

 c. m., central mass; co., collar; i. c, inner cone; p. c, posterior cup. 



7. Scales from the deeper layer of the anterior cap ; X 250. 



8. A somewhat oblique section through one of the siphonal organs, showing the 



concentric layers of scales composing the posterior cap ; X 130. 



9. Antero-posterlor section of one of the branchial organs; X 55. 



10. The lower portion of Fig. 9 ; X 130. 



11. Section of the superficial layers of the upper surface of the organ ; X 270. 



Explanation of letters in Figs. 8-11 : c. m., central mass ; c. t. c, connective 

 tissue capsule ; el., ellipsoidal mass ; ep. epithelial layer ; p. I., pigment layer ; 

 s. c, superficial connective tissue; s. /. c, superficial layer; s. m., superficial 

 membrane. 



12. Sagittal section of the anterior abdominal organ ; X 75. 



c, capsule; c. m., central mass; co , cover; i. c, inner cone; />., pigment 

 layer; p. c, posterior cup; s. c, superficial cells. 



