HoYLE. — Cephalopoda. 



PLATE 10. 



Figs. 1-10. Abraliopsis hoylei. 



1. Ventral aspect, showing the arrangement of the luminous organs; X 2\. 



h^, medio-ventral line dividing anteriorly to pass along the inner margin 

 of the ventral arms and posteriorly to bound the siphonal depression ; /<-, 

 medio-lateral line passing forwards along the outer margin of the ventral 

 surface of the arm ; Ifi, h*, lateral line of organs; s, group of luminous 

 organs on the under surface of the siphon ; wi^, m-, m^, m*, successive rows 

 of organs on the lower surface of the mantle; p, patch of organs from 

 wliich the above lines arise. 



2. Sketch of the interior surface of the left eye, showing tlie position of 



the luminous organs ; X about 3. 



3. Portion of the surface of the mantle, showing luminous organs and 



chromatophores ; X about 20. 



4. Axial section of a luminous organ, from the arm; X loO. 



5. Horizontal section through the lens ; X 150. 



6. Horizontal section througli the upper part of the pigment cup ; X 150. 



7. Similar section more deeply situated ; X 150. 



8. Similar section through the posterior hemisphere; X nearly 200. 



Explanation of letters in Figs. 4-8: c. ^, connective tissue; ('. c, inner 

 cup; i. CO., internal cone; /., lens; p. c, pigment cup; ;). /;., posterior 

 hemisphere; s., sinus. 



9. Section nearly in the equator of the eyeball through one of the larger 



ocular organs ; X 75. 



10. Similar section tiirough one of the smaller ocular organs ; X 75. 



c, lower layer of connective tissue; c.^, connective tissue above and 

 around the lenticular mass; /I, fibrils ; /(. /., horizontal fibrils; i. c, inner 

 mass of connective tissue ; /., lenticular mass ; z., outer zone. 

 Fig. 11. Cranchia scabra. 



View of the mouth and oral aspect of the arms and left tentacle; X 20. 

 Fig. 12. Ari/oiiauta, sp. 



Internal and external aspects of the shell of a young specimen ; X 2. 



