THE FAMILY OF U X I O X I D JE. 



\\l 



TTnlo. Retz. Emended. 

 U. complauatus. Lea. 



Eurynea,* Ra/. Etncn-. 



dad. 



U. prselongus. J?ar. 



Lampsilis,* Ra/. 

 Emended. 

 U. radiatus. Lam. 



Metapfera.' Ra/. 

 Erneoded. 

 U. alatus. Say." 1 



Complanaria. Strain. 

 Emended. 

 Alas, rngosa. Bar. 1 



M;in,Mritana. Schnm. 

 Alas, arcuata. Bar. 



Emended. 

 Ala*, marginata. 

 Sag. 



Strophitas. Ra/. 

 Emended. 

 AD uudiilata. 

 Say." 



Anodonta '' Brug, 

 An. Benedictensli. 

 Lea. 



AOASSIZ'S DIVISION OF 



Hunt If. 



Fringed at both iilphonal open- 

 lap. 



United along the pos- 

 teri.ir edgo % of 

 the length. 



Fringed at posterior half of 

 v.-titnil edge, a tul at branch. 



iili'i iinul BiphoUS. 



Fringed at both siphonal open- 

 iiii,'S having flashy thicken- 

 ings and processes at post. 

 ventral edge. 



Broad expansion upwards. Su- 

 peranal opening long. Buth 

 openings fringed. 



Snperanal opaning long. Both 

 siphonal openings fringed. 



Anal opening of mantle not 

 fringed ; branchial Is fringed. 



Branchial opening fringed. 

 Anat opening large, not 

 fringed. 



Anal opening not fringed. 



Anal opening not frirged. 



ffffifl, 



Free from abdominal *ark, 

 pout, extremity attached to 

 mantle. Eggs filling extent 

 of outer gill. 



Attached to abdom'l Hack. No 

 opening between pedal and 

 u|t]wr gill cavities. Eggs In 

 posterior part of outer gill. 



AttHched. Eg? In posterior 

 pait of outer gilt. 



Attached. Eggs In posterior 

 part of gill. 



Free. United to the mantle to 

 Its margin. Outer gill filled 

 entirely with eggs. 



Free from abdominal sack. 



Post, extrem. not united to 



mantle. 

 Attached to abdominal sack ;* 



attached also to mantle to the 



extremity. 



Attached. Eggs received In the 

 whole extent of outer gill. 



Free. Eggs throughout the gill. 



1 Shells of New Enylrnt'l, IVil, by Win. Stimpson. 



2 r iufucatus, Con. MVIUS in the ulcuholic r<pr'ciin<>ti not to have the anal opening fringed. Also, Fnlo metanerer, H*f. and laerymoHn, La. 



1 I', inultiplicatus. Out of five Urge ooes, three wore attached the whole length, and two open for a abort distance. U. Berlandierii bad four oat 

 of five attached; the fifth slightly open. 



' Kiifluestjue gives no anatomy. This Is his generic description of the genus: "Valves very transverse or very large. Axis almost lateral." 



* Kaf. s;iys; "Mollusc like that of l.'ni<>, but has apparent short syphons." 



1 llaf. says: "Mollusc tike that of Unto." 



1 There is no essential difference in the diagnoses of these three genera. 



' Alii ft. rugoea, Bar. hfi.t not the anal opening fringed. 



' AUs margiuata. Six specimens from Mohawk River were all more or lei 

 Eburnci ; 'Mjs. x 0.3. Homo iittitched, some not. 



10 Prof. A. says: "Anal opening not fringed, but it is very minutely fringed." 



11 An, Ferussaciana, Lea, has pupil I ic on the anal opening. 



Uiiio pu-hikisiis, Lea, has no papilla: or crenulatious on the anal opening. 

 TJnio Kleiuianus, Lea, has no papillae, but has slight creuulations. 

 Uuio Forsheyi, Lea, has no papilla. 

 Uuio Tappanianus, Lea t has no papillae, but has slight crenulations. 



i open ; some a mere point at posterior end of the foot! See 



1'iiio lajvi-^imus, Lea, has no paplllie oifth* anal opening. 

 I'm. i HIandmnns, Lea, has no papillie on the anal opening. 



Vnio H'Hi-lim.'ii-U, Lea, has no papillje. 

 Uuio verrucosna, Bar. baa no paplllc. 



The very uncertain characters by which Prof. Agassiz proposed to divide 

 Family induced me to make notes of many species in which the anatomy did not 

 seem to me to accord with his views. His principal character is the opening or 

 closing of the pedal and upper gill cavities. "Gills free from abdominal sac," and 

 "Gills attached to abdominal sac." 1 Another important character is the possession 



Shells of Xew England, 1>y W. Stiinpson, p. 13. 



