20 MUSSELS OF BIG BUFFALO FORK OF WHITE EIVEE. 



abundant; 12, abundant; 14, abundant; 16, abundant; 17, abundant; 

 18, abundant; 20, common; 21, common; 22, abundant; 23, abundant; 

 24, abundant; 25, abundant. 



Lampsilis luteolus [Lamarck). — Rare; only two examples obtained, 

 both at station 25. They were rather small for river shells, but 

 heavier than the form usually found in lakes. 



Butter^y^ Lamqjsilis ventricosus {Barnes). — Not very abundant, 

 but found distributed throughout most of the length of the stream 

 examined. In all, 22 specimens were found. Most of the shells were 

 well rayed. They exhibited the usual variation in form. One shell 

 collected at station 6 is a short inflated female, bearing a general 

 resemblance to L. ca-pax^ but thick. One shell, obtained at station 8, 

 was small, well rayed, and more closely approaching the shape of 

 L. ovatvs, and had a yellowish epidermis well rayed with green. 



It is only at its best that L. ventricosus is a good button shell, and 

 those of Big Buffalo River are only moderately good shells. 



It was found at the following stations : 2, one live shell ; 3, abund- 

 ant; 5, scarce; 6, scarce; 9, scarce; 21, scarce; 24, scarce. 



Lampsilis hreviculns hrittsi (Simpson) . — This shell is new to the 

 collection of the bureau, and was identified by Mr. Bryant Walker. 

 It agrees fairly well with examples of hreviculus Call, in the Daven- 

 port Academy of Sciences, with which specimens were compared, but 

 is broader and flatter posteriorly. It is a flattened shell bearing some 

 resemblance to a small, thin, considerably produced Lampsilis 

 luteolus, but not markedly inflated postero-ventrally. The numerous 

 green rays are much interrupted and broken up by the lines of 

 growth. Two examples from station 4 have rather rosy nacre. There 

 are 28 shells in the collection. The first five were obtained at station 

 3 and the last one at station 24. 



It was found at the following stations: 4, scarce; G, scarce; 7, 

 scarce; 9, scarce; 11, scarce; 12, scarce; 24, scarce. 



