THE NAIADES OF MISSOURI 451 
spawning, at which time the mother buries her shell in the sand 
up to the siphonal openings, the flaps are waved to and fro exposing 
the ventral edges of the ovisacs through the branchial opening 
while ever now and then sole-shaped conglutinates emerge from 
the anal opening by convulsive jerks. With the eye spots showing 
at the base and the fringed flaps rhythmatically waving one is 
fascinated. Veniricosa is found to be typically bradytictic. The 
geographic distribution for Missouri is wide; however, it is of 
rare occurrence in the streams of North Missouri—never found in 
Northwest Missouri. South of the Missouri it is one of the com- 
monest of shells. 
Lampsilis ventricosa satura (Lea). 
(‘Plain Pocket Book.’’) 
Pl. XXVIII, Figs. 107 A—B. 
1852— Unto satur Lea, Pr. Am. Phil. Soc., V., p. 252; Tr. Am. Phil. 
DOCH Aero s2 iN 2OS mn. Meno Vly, trea nGs 
1900b—Lampsilis ventricosus satur (Lea) Simpson, Pr. U. S. Nat. Mus. 
DOXAT | D452: 
ANIMAL CHARACTERS :—Identical in every way to the parent 
species. 
SHELL CHARACTERS:—Also identical to the species except in 
its uni-coloration of epidermis which is rather a dark-brownish. 
All shells collected by the writer for this State are also smaller 
when mature. 
Sex Length Height Diameter Locality 
Q@ 88 x 55 x 45mm—(Black R., Williamsville) 
So 75 X 54 x 42mm—(White R., Hollister) 
MISCELLANEOUS REMARKS:—This subspecies is only found 
in the Southwest. For this State it is definitely reported by Mr. 
Walker for the Black River., Popular Bluff. The writer collected 
some of these forms of ventricosa from the same stream a few miles 
north. The Black is a metropolis for ventricosa where it is found 
in all forms, since this species is liable to intergrading—satura 
being one of these intergradations. Yet its rayless character (like 
that of capax) would make it worthy of a name. 
