26 



BULLETIN 37, UNITED STATES NATIONAL MUSEUM. 



SKETCH OF GENERAL ARRANGEMENT. 



L Order Arfchropomata. 



A.— CLASS BEACHIOPODA. 



I II. Order Lyoporaata. 



B.— CLASS PELECYPODA. 



I. Order Prionodesmacea. 



1. Suborder Ostracea. 



2. Suborder Auomiacea. 



3. Suborder Pectinacea. 



4. Suborder Mytilacea. 

 [5. Suborder Naiadacea. 



6. Suborder Trigoniacea]. 



7. Suborder Arcacea. 



8. Suborder Nuculacea. 



9. Suborder Solenomyacea. 



II. Order Teleodesmacea. 



1. Suborder Carditacea. 



2. Suborder Leptonacea? 



II. Order Teleodesmacea — Continued. 



3. Suborder Luciuacea. 



4. Suborder Cbamacea. 



5. Suborder Cardiacea. 



6. Suborder Veiieracea. 



7. Suborder Tellinacea. 



8. Suborder Mactracea. 



III. Order Auonialodesmacea. 



1. Suborder Anatinacea. 



2. Suborder Myacea. 



3. Suborder Soleuacea ? 



4. Suborder Ensipbonacea. 



5. Suborder Adesmacea. 



C— CLASS SCAPHOPODA 

 I. Order Solenocoucbia. 



D.— CLASS GASTROPODA. 

 aa. Subclass Anisopleura. 



I. Order Pteropoda. 



1. Suborder Thecosomata. 



2. Suborder Gymnosomata. 



II. Order Opistbobrancbiata. 



1. Suborder Tectibrancbiata 



Superorder Euthyneura. 



[III. Order Nudibrancbiata.] 

 IV. Order Pulmonata. 



1. Suborder Stylommatophora. 



2. Suborder Basoramatopbora. 



I. Order Ctenobrancbiata. 



B. Superorder Streptoneivra. 



Suborder Ortbodouta. 



a. Superfaniily Toxoglossa. 



I. Superfaniily Rbacbiglossa. 

 Suborder Streptodouta. 



a. Superfaniily Ptenoglossa. 



6. Superfaniily Gyninoglossa. 



I. Order Ctenobrancbiata — Continued. 

 2. Suborder Streptodouta— Cont'd. 



c. Superfatnily Taeuioglossa. 



d. Superfaniily Docoglossa. 



e. Superfamily Rbiphidoglossa. 

 /. Superfamily Zygobranchia, 



56. Subclass Isopleura. 



C. Superorder Folyconclicp,. 



I. Order Polyplacopbora. 



a. Superfamily Eocbitonia. 

 6. Superfamily Opsicbitonia. 



E.— CLASS CEPHALOPODA. 

 I. Order Dibranchiata. 



1. Suborder Octopoda. 



2. Suborder Sepiopbora. 



Note.— Tbe reader will understand tbat this sketch does not pretend to complete- 

 ness, except for the following tables. 



