Yy DESCRIPTIONS OF 



olive-yellow, shining, obscurely radiate, with not very distant lines of growth; 

 umbonial slope slightly raised and rounded ; cardinal teeth very small, compressed, 

 oblique, double in the right and single in the left valve ; lateral teeth long, acicular and 

 somewhat curved ; anterior cicatrices confluent and very slightly impressed ; posterior 

 cicatrices confluent ; dorsal cicatrices in a row across the cavity of the beaks ; cavity 

 of the shell somewhat deep and rounded ; cavity of the beaks shallow and rounded ; 

 nacre white and slightly iridescent. 



Remarlcs. — This small species, the description of which is made from a single 

 specimen, has the usual type of the Unimies from the Asiatic Islands. And, what is 

 not uncommon in species from that quarter of the globe, it has its lamellate car- 

 dinal tooth double in the right and single in the left valve. In outline it is very near 

 to affinis, (nobis), but is a much smaller, thinner and more' compressed shell. 



Unio Goascoranensis. pi. 41, fig. 139. 



Testa, Isevi, ellipticS., .subcompressu, postice obtuse angulata, vald^ insequilaterali ; valvulis suberassis, 

 antice crassioribus; natibus prominuHs ; epidermide fuscescente, transverse striata; dentibus car- 

 dinalibus parviusculis, suberectis crenulatisque ; lateralibus sublon,s;is subrectisque ; margarita alba, 

 et iridescente. 



Shell smooth, elliptical, rather compressed, obtusely angular behind, very inequi- 

 lateral ; valves rather thick, thicker before ; beaks a little prominent ; epidermis 

 brownish, transversely striate ; cardinal teeth rather small, somewhat erect and 

 crenulate ; lateral teeth rather long and nearly straight ; nacre white and iridescent. 



Imio Goascoranensis, Lea. Proc. Acad. Nat. Sci., 1859, p. 118. 



Hab. — River Goascoran, Honduras, Pacific Slope. J. L. Le Conte, M. D. 



My cabinet and cabinets of Major Le Conte and Academy of Natural Sciences. 

 Diam. -8, Length 1-3, Breadth 2-3 inches. 



Shell smooth, elliptical, rather compressed, obtusely angular behind, very inequi- 

 lateral, obliquely rounded before ; substance of the shell rather thick, thicker before ; 

 beaks a little prominent ; ligament rather long, somewhat thick and dark brown ; 

 epidermis brownish, sometimes inclmed to olive, transversely striate, almost furrowed ; 

 umbonial slope rather low and flattish ; posterior slope rather narrow and but slightly 

 raised ; cardinal teeth rather small, somewhat erect, crenulate, disposed to duplication 

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

 enlarged towards the end ; anterior cicatrices distinct and well impressed ; posterior 

 cicatrices distinct and moderately well impres.sed ; dorsal cicatrices placed across the 

 centre of the cavity of the beaks ; cavity of the shell moderately deep ; cavity of the 

 beaks shallow and obtusely angular ; nacre white and iridescent. 



/Soft parts. — Branchial uterus . No ova were found in the only specimen 



received. It is probably a male. Branchial rather large, very thin, slightly curved 

 below, inner one rather the larger, free nearly tlie whole lenath of abdominal sack. 



I 



