432 UNIONIDiE, THEIR SOFT FARTS 



opening rather large, with numerous small brownish papillae. Anal opening small, 

 with minute brownish crenulations on the inner edges, scarcely amounting to papillae. 

 Super-anal opening large, blackish along the edges, united for a short distance below. 

 Color of the mass dirty white inclined to yellowish, the lower portion of the foot being 

 blackish. 



Embryonic shell elongately pouch-shape, clear white, has no hooks. See Jour. 

 Acad. Nat. Nat. Sci. (2), vol. iv. pi. 5, fig. 6, and Obs. vol. vi. p. 47. 



Cincinnati, Ohio, J. Clark. 



Remarks. — This species, so well characterized by the form and markings of the 

 outward hard parts, belongs to that group of Uniones which have not well developed 

 papillae on the edges of the anal opening, but which still are not entirely smooth, 

 being somewhat crenulate. 



■s 



Unio iEsorus, Green. Journ. Maclurean Lyceum 1827, pi. 3. 



Branchial uterus . No ova were found here, but they were in the ovarium, 



and had the remarkable character of being red. Branchiae rather large, somewhat 

 thick, rounded below, inner ones much the larger, free nearly the whole length of 

 the abdominal sack. Palpi rather large, rather thick, united about one-fourth down 

 the posterior edges. Mantle very thin, with a broad margin. Branchial opening 

 rather large, with numerous brownish papillae in clusters. Anal opening very large, 

 with numerous very minute papillae. Super-anal opening very large, united below 

 for a short distapce. Color of the mass yellowish, inclining to salmon, the foot being 

 deep salmon. 



Cincinnati, Ohio, J. Clark. White River, Indiana, D. H. Shaffer. 



Remarhs. — This is one of the only three species which I know to have red ova. 

 The other two are rubiginosus and subrotundus* It is to be regretted that we have 

 not a specimen of iEsopus with the matured embryonic shells, to judge of their form 

 as well as to ascertain if they be red in the branchial uterus. 



Unio ellipsis, Lea. Trans. Amer. Phil. Soe., (2), vol. iii. pi. 4, fig. 4. Obs. vol. i. p. 10. 



A single specimen only — a male — was received. Branchial rather large, thin, 

 rounded below, inner ones much the larger, united the whole length of the abdominal 

 sack. Palpi rather large, thin, subtriangular, united half way down the posterior 

 edges. Mantle thin, with a rather large margin, thickened at the edges, and slightly 

 crenulate below the branchial opening. Branchial opening very large, with numerous 

 very small, brownish papillae. Anal opening rather small, brownish, with very 

 minute crenulations on the inner edges. Super-anal opening large, united for a short 

 distance below. Color of the mass yellowish, inclining to salmon, 



Cincinnati, Ohio, J. Clark. 



*See Remarks, page 416. 



