67. 



Pig, 2. Left siiell valve, seen obliquely from tlie dorsal 



margin. 



Pig. 3. Adult specinen represented as seen from the riglit 



side, witii the right shell valve and mantle lobci 

 removed. The siphons are sho^wn cut longitudi- 

 nally. 



Pig. 4, Same as the above v;ith the right palp and gill 



removed, figured to show the relations of internal 

 organs. The neives leaving the ganglia are 

 shown only on the left side. (I> argoly recon- 

 structed) . 



Pig. 5. Specimen about 1 mm. long. Represented as a 



partially transparent object, seen from the right 

 side, after the right shell valve and mantle lobe 

 have been removed. (.largely reconstructed). 



Pig. 6, Tip of a retracted siphonal tentacle. 



Pig. ?. Portion of an extended siphonal tentacle, with a 



swelling caused by the pressure of the blood, seen 

 as a tran.sparent object. 



Fig. 8. Transverse section of a siphonal tentacle. 



