388 



DECAPODA 



As a rule the rostrum is the only portion which has been 

 preserved. 



FAi\r. 3. Belosepiidae. — Phragmocone short, slightly curved, 

 chambers small, placed at the posterior end of a sepion, rostrum 

 solid, obtuse. — Eocene (Paris, Bracklesham, etc). 



Fam. 4. Belopteridae. — Sepion not known ; phragmocone 

 curved, siphuncle on the ventral margin, rostrum well developed, 

 pointed. Principal genus, Spirulirostra. — Miocene of Turin. 



These two families, with their small, curved 

 phragmocone and (in the case of the Belose- 

 piidae) large sepion, are clearly intermediate 



Fig. 247. — Shell of Spuula Peronii Lam A, Outside view ; B, 

 showing last chamber and i^osition of siphuncle ; C, in section, 

 showing the septa and coui'se of siphuncle ; D, shell broken 

 to show the convexity of the inner side of the septa ; E, i^or- 

 tiou of a septal neck. 



Fig. 2i%.—Spirula Per- 

 onii Lam. : d, ter- 

 minal sucker ; f, 

 funnel ; s^, s->, pro- 

 jecting portions of 

 shell, the internal 

 part of which is 

 dotted in. (From 

 Owen and A. Adams 

 combined.) 



between the Phragmophora and Sepiophora. Some authorities 

 place them with the latter group. 



B. Sepiophora. — Shell internal, consisting usually of («) an 

 anterior cancellated portion, (&) a posterior laminated portion, 

 the laminae enclosing air. It terminates in a very rudimentary 

 phragmocone and a rostrum, but there is no siphuncle. 



Fam. Sepiidae. — Eyes with cornea complete, body oval, fins 

 narrow, lateral, as long as the body, generally united behind ; 

 sessile arms short, tentacular arms long, acetabula generally in 



