THE NAUTILUS. 137 



keeled, and cordate at the beaks. Cavity of the shell rather deep 

 and uniform ; cavity of the beaks well under the dorsum, blunt 

 within. Cardinal teeth, low, compressed and double in both valves 

 and nearly tubercular. Nacre white within the pallial Hue, and 

 darker and iridescent exterior to it. Lateral teeth small, short,, 

 remote from the cardinals, and straight in the groove, but making a 

 slight angle from the dorsal plate at the anterior end of the liga- 

 ment, which is * of an inch long. Width 11 inches, length ]^, di- 

 ameter f of an inch. 



Habitat : Ocklocknee River, Leon Co., Fla. 



Remarks: Affinity, U. subaiir/ultitiix Lea. Our shell differs from 

 this in being more polished, thinner, rays broader, those of the an- 

 terior end sweeping around in curves. The shell cavity is much 

 deeper and broader. The beak cavities are much larger, and the 

 shell substance white instead of incarnate. We take pleasure in 

 naming this species, which is probably not exceeded in pictorial 

 beauty by any known Unio in North America, in honor of Dr. 

 Reynold J. Kirklaud, of Grand Rapids, Michigan, who is a vigor- 

 ous investigator in conchologv. 



Unio Burtchianus sp. n.i\ . 



Shell uniformly solid, though not thick, oblong-elliptical, flattish, 

 inequilateral, smooth and polished, with a slight constriction near 

 the middle. Sides rounded, anterior end rounded, pointed behind 

 with a very short truncation. Dorsal and basal margins uniformly 

 curved. Epidermis reddish, nearly occulted with dark green rays 

 running over all the surface, which are grouped in irregular fasci- 

 cles, darker and densely striate on the posterior slope. Growth 

 lines almost invisible. Beaks small and low, slightly rounded. 

 Umboual slope subangular, with a fainter ridge back of it, making 

 a binngulation behind. Beak cavities very slight, confluent with a 

 cavity under the lateral teeth. Shell cavity moderate and oblong. 

 Cardinal teeth erect, light, crenulate, with an oblong groove in the 

 cardinal of the right valve. The inner lateral tooth thickened and 

 upturned at the end. Posterior cicatrices confluent, anterior dis- 

 tinct, all well impressed. Pallial impression distinct and crenulate. 

 Nacre salmon within the pallial line and purplish exterior to it. 

 Width 2i inches, length H, diameter f . 



Habitat: St. Mary's River, Nassau Co., Florida. 



Remarks : Affinity, U. lehmanii, herein described, in which the 

 distinction is made between these species. It is named in honor of 



