LIST OF PLATES AND FIGURES. 



Frontispiece. Photographs of a model of a male squid in The American Museum of Natural History* 



Plate I, Fig. 1. Cephalic and preorbital cartilages (enlarged four diameters), right-ventral aspect. 



„ 2. The gastro-caecal opening seen from below. 



„ 3. Section thru a symmetrical sucker. 



„ 4. „ „ an unsymmetrical sucker. 



„ 5. Distal end of spermatophore. 



„ 6. The arterial system. 



„ 7. The alimentary canal. 



Plate II, Pig. 8. The venous system. 



„ 9. Venous and arterial systems. 

 Outer side of the sperm duct. 

 Inner side of proximal portion of the sperm duct. 

 Diagram of the spermatophoric gland. 

 Outer side of oviduct. 

 Inner side of oviduct. 

 The nervous system , right aspect. 



The nervous system, anterior aspect. 



A sagittal section of the head. 



A median section of a male squid, left side. 



„ , „ „ „ „ right side. 

 Lens of a very young squid. 

 Ciliary body of squid 20 mm. long. 

 Horizontal section through the eye and one side of the head. 



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Plate III, Pig 



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PLATE I. 



Pig. 1. Cephalic cartilage (skull) and preorbital cartilages. 

 G.P. cephalic process. 

 F. 1 large (oesophageal) foramen. 



F? foramen for the vein which connects the orbital sinus and anterior vena cava. 

 L.Lig. lateral ligament. 

 L.P. lateral process. 

 P.O. preorbital cartilage. 

 P.P. pedal process. 



Pig. 2. Lower aspect of the gastro-caecal opening. 

 C. caecum. 

 E. oesophagus. 

 /. intestine. 



P. pancreas with the hepatico-pancreatic duct. 

 St. stomach. 



