KAIADES OF MISSOURI 53 



Quadrula quadrula Rafinesque. 

 ("Maple Leaf," "Monkey Face," "Tear vShell.") 

 PL IX., Fig. ig; PI. XV 11 1., Fig.s 45 A—F. 



1820 — Quadrula quadrula Rafinesque, An. Gen. Sci. Phys. Brux. 



P- 305- 

 1828 — Unio lacrymosus Lea, Tr. Phil. Soc., Ill, p. 1272, pi. VI, fig. 8. 

 1 83 1 — Unto asperrimus Lea, Tr. Am. Phil. Soc, IV, p. 71, pi. V., fig. 3. 

 ^834 — Unio quadrulus Say, Am. Conch, VI. 



iSgS— Quadrula lachrymosa Baker, Moll. Chicago, Pt. I, p. 83, pi. 

 XXV., fig. I, XII, fig. 2. 



ANIMAL CHARACTERS. 



Nutritive Structures: — Branchial opening rather large 

 with arboreal papillae; anal slightly crenulate; supra-anal very 

 large closely connected to anal by mantle edges; palpi very long 

 united about two thirds of their length antero-dorsad and heavily 

 vein marked ; inner laminae of inner gills free from visceral mass ; 

 color of most soft parts tanned flesh color. 



Reproductive Structures : — All four gills marsupial ; ovisacs 

 wide in middle transversely, ventral positions being divided, 

 giving the white conglutinates a double or triple split appearance, 

 septa thickened at intervals leaving thin transparent elongated 

 spots arranged regularly and transversely in the conglutinates; 

 glochidia not found by writer ; Dr. Surber reports it as the smallest 

 of the Oiiadrulae; color of charged marsupia brown; crenulated 

 flap on post-dorsal part of foot; probably sexual in function as 

 only noted in females. 



SHELL characters. 



External vStructures: — Shell medium in size, subquadrate 

 to subtrigonal, dorsal ridge more or less alated with costae on 

 !^ lopes undulated or sulcated post-umbonal ridge prominently 

 angled set with coarse tubercles, a valley or radial furrow in front 

 bounded anteriorly by a row of more or less irregularly placed 

 tubercles on center of inflated disk, presenting the appearance 

 of drops of melted wax; epidermis varies from olive green to chest 

 nut brown or even black, in some instances faintly rayed anteriorly 

 and with continuations of green paintings ventrad to some of the 

 tubercles; beaks high, full, furrowed, post-obliquely, sculptured 

 with corrugated, concentric ridges that break into great numbers 

 of small tubercles out on the umbonal region. 



