1 84 THE NAIADES OF MISSOURI 



of beaks deep, of the shell moderately deep. Nacre white, decidedly 

 irridescent posteriorly." 



Dr. Scammon reports Powellii as a very rare shell for Kansas, 

 being found in only one locality. Spring River, Baxter vSprings, 

 and further states that this species may be distinguished from 

 L. luteola, its nearest ally in local waters, by the smaller and less 

 pointed cardinals and the thinner, squarer and less inflated shell. 

 Simpson states that Powellii is also found in Salina and Clinton, 

 Arkansas, and in Guadaloupe River, Texas. The fact that Mr. 

 Simpson found this rare shell in the Neosho basin of this State 

 its range is more determined. 



Lampsilis luteola (Lamarck). 



("Fat Mucket.") 



PL XXVIII, Figs. 103 A—F. 



1819 — U7iio luteola Lamarck, His. Sans. Vert., VI, p. 79. 

 1898 — Lampsilis luteola Baker, Mol. Chicago, Pt. I, p. 103, pi. XI, 

 fig. 12; pi. XXXVII, fig. 12. 



ANIMAL CHARACTERS. 



Nutritive Structures :— Branchial opening large with 

 numerous papillae; anal slightly crenulated; supra-anal well 

 separated by thick mantle connection; inner laminae of inner 

 gills connected to visceral mass; palpi short, wide; color of soft 

 parts dingy white, mantle border blackened posteriorl3\ 



Reproductive Structures: — Mantle edge antero-ventrad to 

 branchial opening with long spotted flap at the end of which are 

 two or three finger like tentacles and about midway an eye spot 

 appears; marsupium large, kidney-shape, consisting of numerous 

 distinct ovisacs that hang down toward the mantle flap in beaded 

 rows; conglutinates white, large, subsolid; glochidium rather 

 large (uniformly smaller for lacustrine luteola), subelliptic, spineless, 

 measuring 0.250 x 0.290mm. 



SHELL characters. 



External Structures: — Shell broadly elliptic, narrowly 

 rounded before, broadly rounded behind; female shell greatly 

 inflated, rather truncated posteriorly expanded post-ventrad, male 

 shell pointed posteriorly; disk smooth; umbones large but low. 



