26 



BULLETIN 37, UNITED STATES NATIONAL MUSEUM. 



SKETCH OF GENERAL ARRANGEMENT. 



C. CLASS SCAPHOPODA 

 I. Order Solenocouchia. 



D. CLASS GASTROPODA. 

 aa. SUBCLASS ANISOPLEURA. 



I. Order Pteropoda. 



1. Suborder Thecosomata. 

 2 Suborder Gymnosomata. 



II. Order Opistbobraucbiata. 



1. Suborder Tectibrauchiata. 



A. Superorder Euthyneura. 



[III. Order Nudibrancbiata.] 

 IV. Order Pulmonata. 



t. Suborder Stylommatophora. 

 2. Suborder Basommatophora. 



B. Superorder Streptoneura. 



I. Order Ctenobrancbiata. 



1. Suborder Orthodonta. 



a. Superfaniily Toxoglossa. 

 &. Superfatnily Rhacbiglossa. 



2. Suborder Streptodouta. 



a. Superfamily Ptenoglossa. 

 6. Superfamily Gymnoglossa. 



I. Order Ctenobrancbiata Continued. 

 2. Suborder Streptodonta Cont'd. 



c. Superfamily Taenioglossa. 



d. Superfamily Docoglossa. 



e. Superfamily Rbiphidoglossa. 

 /. Superfamily Zygobrancbia. 



6&. SUBCLASS ISOPLEURA. 

 C. Superorder Polyconch<B. 



I. Order Polyplacopbora. 



a. I uperfamily Eocbitonia. 



b. Superfamily Opsicbitonia. 



E. CLASS CEPHALOPODA. 

 I. Order Dibranchiata. 



1. Suborder Octopoda. 



2. Suborder Sepiopbora. 



NOTE. Tbe reader will understand that this sketch does not pretend to complete- 

 ness, except for the following tables. 



