130 THE NAIADES OF MISSOURI 



locally in the White, Black, and Neosho River basins. Simpson 

 reports it for the Red River, Arkansas; Prof. Isely and Rev. 

 Wheeler also report it for Arkansas and Oklahoma. Thus it seems 

 to have supplanted fasciolarsis { = phaseohis) of the Tennessee 

 drainage for the Southwest. 



Genus Obliquaria Rafinesque. 



1830 — Obliquaria Rafinesque, Ann. Gen. Sci. Phys. Bru.x., p. 301. 

 1900b, Simpson, p. 610. 



(Type Obliquaria reflexa Rafinesque.) 



Animal Characters: — Branchial opening large with papillae; 

 anal crenulated; supra-anal high with moderately short mantle 

 connection to anal; inner laminae of inner gills free from the 

 visceral mass except for a short distance anteriorly; palpi short 

 and small; soft parts grayish; marsupium occupying only outer 

 gills and consisting of 5-7 ovisacs placed posterior to the center 

 of the gill and when gravid extending far beyond the edge of sterile 

 marsupium; glochidia medium in size, semicircular, hinge-line 

 with a slight up-curve in centre; conglutinates large, white, 

 club-shaped, glochidia scattered all through the conglutinated 

 mass. 



Shell Characters: — Shell medium in size, thick roundly 

 trigonal, inflated; disk of one valve with row of large knob-like 

 nodules running from beaks centrally ventrad and alternating 

 with the knobs on the other valve; beaks sculptured with two 

 or three concentric bars which, although heavy, are not well 

 defined; epidermis greenish-yellow to brown with paintings of 

 numerous interrupted rays; cardinals prominent and ragged; 

 laterals short nearly straight; beak and branchial cavities not 

 very deep; nacre white; female shell smaller and slightly inflated 

 post-ventrad. 



Miscellaneous Remarks: — 0. reflexa is the type and only 

 member of this genus known thus far and is one of the most easily 

 identifiable of all the Lampsilinae not only in its most unique 

 marsupium, but also in the knobbed sculpture of its disk. The 

 sex dimorphism of the shell for this type is rather peculiar as 



1836, pi. XXXVI, fig. 23) is the Pty. clintonense Simpson (1900-a and b) 

 and hence this species, whose type locality is the Current River, Missouri, 

 should be: — Ellipsaria occidentalis (Conrad), 



