262 DESCRIPTION OF NEW 



Shell smooth, elliptical, rather inflated; valves somewhat thick; beaks somewhat prominent; epidermis dark- 

 brown; cardinal teeth rather small and erect; lateral teeth long and nearly straight; nacre white and iridescent. 



Hab. Abbeville District, S. C. J. P. Barratt, M. D. 

 My cabinet and cabinet of Dr. Barratt. 

 Diam. .7, . Length 1, Breadth 1.7 inches. 



Shell smooth, elliptical, rather inflated, rounded before and angular behind; substance 

 of the shell rather thick, thinner behind; beaks somewhat prominent, submedial; ligament 

 rather short and thin; epidermis dark-brown, with obscure rays, very smooth and polished; 

 marks of growth distant, regular and well marked; cardinal teeth rather small, compressed, 

 double in the left and single in the right valve; lateral teeth long, nearly straight and 

 enlarged at the posterior end; anterior cicatrices distinct; posterior cicatrices confluent; 

 dorsal cicatrices placed on the under side of the cardinal tooth; cavity of the shell rather 

 shallow; cavity of the beaks shallow and angular; nacre white and iridescent. 



Remarks. — Dr. Barratt sent me three specimens of this species, one only being adult. 

 Neither of them have the beaks sufficiently perfect to show any undulations. In outline 

 it resembles U. concavus, (Nobis,) but it is more compressed, and differs much in the colour 

 of the epidermis and the rays. The adult specimen is slightly salmon coloured in the 

 cavity of the beaks. One of the younger specimens is distinctly salmon coloured. 



Unio pygjleus. PI. XV. Fig. 14. 



Testa Isevi, elliptica, sitbeompressd, striata ; valvulis subtcnuibus ; natibus subprominentibns ; epidermide 

 tenebroso-fuscd ; dentibus cardinalibus parvis ; htterulibiis linearis subcurvisgue ; margarita cxruled et 

 iridescente. 



Shell smooth, elliptical, rather compressed, striate; valves rather thin; beaks somewhat prominent; epidermis 

 dark-brown; cardinal teeth small; lateral teeth linear and slightly curved; nacre bluish and iridescent. 



Hab. Abbeville District, S. C. J. P. Barratt, M. D. 

 My cabinet. 

 Diam. .4, Length .7, Breadth 1.2 inches. 



Shell smooth, elliptical, rather compressed, striate, rounded before and angular behind; 

 substance of the shell rather thin, thicker before; beaks somewhat prominent; ligament 

 short and thin; epidermis dark-brown, striate, with obscure rays, and slightly polished; 

 umbonial slope angular; marks of growth indistinct; cardinal teeth small, compressed; 

 lateral teeth rather long, linear, slightly curved, and thickened at the posterior end ; 

 anterior cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices in the centre 

 of the cavity of the beaks; cavity of the shell shallow; cavity of the beaks small and 

 angular; nacre blue and very iridescent behind. 



Remarks. — This is a very small species, and a single valve only, (the right) has been 

 received by me. I do not think this is quite adult. The beak is not sufficiently perfect 

 to observe any undulations. This shell is about the size of U. fabalis, (Nobis,) and 

 parvus, Barnes, but cannot be confounded with either of them. It is a thinner shell than 

 the former and less inflated than the latter. 



