XX SYNOPSIS OF 



STROPHITUS, Raf., emend. Gills attached; eggs received in the whole extent of the outer gill; 

 anal opening not fringed. (Anodonta undulala, Say.) 



ANODONTA, Brug. Gills free; eggs throughout the gill ; anal opening not fringed. (Anodonta 

 Benedictensis, Lea.) 



Soon after the appearance of Dr. Stimpson's publication from Prof. Agassiz's 

 MSS. I tabulated his divisions and those of Prof. Troschel for my own use. To these 

 I occasionally added notes, and I produce the tables here for reference. 



TROSCHEL'S DIVISIONS OP THE FAMILY UNIONID^E." 



DiAG508i8 OP THK FAMILY OF UsioxiD^. Shell with epidermis; without emargination ID the mantle; two muscles, tho anterior of which makes 

 commonly three impressions in the shell ; one exterior ligament ; mantle without branchial and anal tubes, and without retractile muscles; two I-M.-I -mil 

 and two internal mouth lips which are large and rounded, and internally perpendicularly striate; two branchiae oa each side, united to each other 

 behind the foot for the whole length ; branchial filaments not separate. All live in fresh water. 



Tnio. Retz. 



tumulus. 



Jlargaritana. Sch. 

 margaritifcra. 



Mouth Lips. 



Wider than long, 

 united to mid. post. 

 margin. 



Wider lhan long, 

 united to % post mar- 

 gin. 



Mantle, 



Margin entirely open. 



Entirely open. 



Branch) ce. 



Outer united to mantle to ex- 

 tremity. Inner not united to 

 foot. 



Outer is free posteriorly. In- 

 ner united to foot anteriorly, 

 but free the greater part. 



Foot. 



Tungue- shaped, thick ; pro- 

 duced anteriorly. 



Tongue-shaped, thick ; some- 

 what produced anteriorly. 



Hyria. Lam. Wide as long, not Margin inf. open. Post, closed Outer united to the mantle to Tongue-shaped, thick ; some- 



syraiatophora. united. to make hranchial and anal extremity. Inner united to what produced auteriorly. 



aperture. the foot. 



Castalia. Lam. 



Dipsas. Leech. 



*Anodonta. Lam. 

 cellensis. 



Itidina. Lam. 

 cselestis. 



Spatha. Lea. 

 rubeus. 



Little wider than long. 



Animal unknown. 



Wider than long, 

 united to middle of 

 posterior margin. 



Longer than wide, 

 not united. 



Longer than wide, 

 not united. 



Mycetopus. D'Orb. Longer than wide. 



Margin inf. open. Post, closed 

 to make bnuichial and anal 

 apertures. 



Margin entirely open. 



Margin united as far as the 

 foot, so that branchial and 

 anal apertures are closed. 



Margin closed behind, so that 

 the bran, and anal apertures 

 are closed ; entirely open on 

 the under margin. 



Margin open to anal aperture, 

 which is clot-ed. 



Outer united to mantle to ex- 

 tremity. Inner ? 



Outer united to mantle to ex- 

 tremity. Inner not united to 

 foot. 



Outer united to mantle to ex- 

 tremity. Innereutirely unit- 

 ed to foot. 



Outer united lo mantle to ex- 

 tremity. Inner not united to 

 foot. 



Outer entity united. The 

 inner ? 



Tongue-shaped, thick; some- 

 what produced anteriorly. 



Tongue-shaped, thick ; some- 

 what produced auteriorly. 



Tongue-shaped, thick ; some- 

 what produced anteriorly. 



Tongue-shaped, thick; some- 

 what produced anteriorly. 



Produced and widened into a 

 knob. 



1 Wieyman's Archives, 1847, v. 13. 



* The genera Unio and Anodonta are described exactly the same ! ! 



