66 NEW UNIONID.* OF THE 



very thick, very short, blunt at the ends, roughly striate and double in both valves ; 

 anterior cicatrices very distinct and very deeply impressed ; posterior cicatrices con- 

 fluent; dorsal cicatrices numerous along the lower side of the cardinal tooth in a 

 row leading into the cavity of the beak ; cavity of the shell rather deep ; cavity of 

 the beaks deep and subangular, nacre silver white, very pure and iridescent. 



Soft Parts. — Branchial titenos was not charged, but the ovarium of each of three 

 females examined, was filled with ova. BranchicB rather small, semicircular, inner 

 ones much the larger, the whole four leaves remarkably thick and were without any 

 ova, free nearly the whole length of the abdominal sack. Pa?2ji large, oblique, suboval, 

 united more than half way down the posterior edges. Mantle rather thin, very much 

 enlarged anteriorly, and superiorly thickened at the edges, with a wide palleal border. 

 Branchial ojoening large, with numerous brownish papillse in groups and diverging. 

 Anal opening rather small and without any Papilloi or crenulations on the edges. 

 Super-anal openiiig very long and deep, slightly colored on the inner edges and united 

 below for a short distance. Color of the mass whitish. 



Remarlis. — I owe to the kindness of Bishop Elliott a fine suite of nearly all ages of 

 this beautiful species, among the finest of all the tuberculate group. It is nearly 

 allied to Bumphianus (nobis) and metanever Raf., and is the largest of the sjiecies which 

 belong to the group which embraces those species. It difiers from them in having 

 a smooth umbonial slope, quite raised and rounded, while metanever has a number 

 of regular large tubercles and Bumphianus a larger number of small irregular tuber- 

 cles on this slope. Some individuals have tubercles over the whole disk except on 

 the umbonial slope, while others have only a few on the upper portions of it. Towards 

 the beaks and on them the tubercles are smaller, thickly set and disposed to arrange 

 themselves in rows forming an acute angle. The tubercles are usually pointed below 

 and lie like tears on the side as they do in lacrymosus (nobis). The teeth are enor- 

 mously large and massive and very much corrugated. The latei'al tooth very short 

 and thick is in a direct line from the tip of the beak to the posterior margin. All the 

 cicatrices are deeply impressed, including the palleal. I have great pleasure in naming 

 this beautiful species after my friend, Mr. Thomas Bland, who has done so much for 

 American conchology. 



Unio concestator. pi. 12, fig. 48. 



Testa Isevi, clliptica, inflata, inacquilaterali, anticc rotundata j valvulis subcraseis, anticecrassioribus; natibus 

 prominulis ; cpidermide nigricente, eradiata, transverse striata ; dentibus cardinalibus subcrassis, in 

 utroque valvule duplicibus crenulatisque ; lateralibus longis subcurvisque ; margarita vel purpurea 

 vel salmonis colore tincti et iridescente. 



Shell smooth, elliptical, inflated, inequilateral, rounded before ; valves rather thick, 

 thicker before ; beaks somewhat prominent ; epidermis nearly black, without rays, 



