NAIADES OF MISSOURI • 37 



\Var?av. specimen. They are rotund, inflated, epidermis greenish 

 and approach the spherical form of the juvenile peruviana. Beaks, 

 even in these young shells, are too eroded to make out the sculp- 

 tural markings. 



Miscellaneous Remarks: — Since Ajnb. pcrplicata is a 

 Southern species it is only found in this state in typical form in 

 the south drainage of the Ozark Uplift. Personal collections 

 made by the writer from the vSt. Francis are found to compare 

 well with typical perplicata shells received from Mr. Frierson and 

 taken from type localities. This species is also sparingly found 

 in the Osage where its subspecies, quiniardi of Cragin is the pre- 

 dominant form of Amhlemae, and from which it is distinguished 

 by the smaller, more compressed, and much plicated shell of 

 the latter. Under the description of Amh. rariplicata the dis- 

 tinguishing features between that species and perplicata have 

 been mentioned. At first the inclination was to set this species 

 down in the synonomy of rariplicata from general shell features, 

 but the few specific differences in shell as well as that of geo- 

 graphic range are enough to make it distinct. This species is 

 tachytictic, being found gravid by Wilson and Clark (1914, p. 42) 

 from May until July inclusive. The writer examined many through- 

 out June and July to find none gravid; however, its subspecies 

 iquintardi) was found gravid during these months and because 

 of these fact some reason was given that this smaller, compressed 

 form was only the female of the larger one, just as seen in case of 

 Plagiola securis or Ohovarid retusa. 



Amblema perplicata quintardi (Cragin) 



("Little Blue-Point," " Multiplicate.") 



PL XVI . Figs. 38 A—D. 



1887 — Unio quintardii Cragin, Bull. Wahb. Coll., II, p. 6; Pilsbry, 

 Pr. Ac. N. Sci. Phila., 1892, p. 131, pi. VII, figs, 1-3. 



iSgi — Unio pilsbryi Marsh, Nautilus, V. pp. i and 2; Nautilus, VII, 

 1893, pi. I, figs. 7 and 8. 



ANIMAL CHARACTERS. 



Nutritive Characters: — Similar to those of the species, 

 having its anal and supra-anal openings often unconnected by 

 mantle edges, free laminar edges of inner gills, palpi mostly con- 

 nected by their edges, and being colored a dirty white or tan; 

 reproductive structures also rather identical in possessing marsupia 



