AND EMBRYONIC FORMS. 403 



Embryonic shell ovato-pouch-shape, very nearly the same with parvus. 



Remarks. — The female of this species has a spongy mass on the inside of both 

 sides of the mantle, below the branchial opening, like that of parvus,* resembling 

 the lachrymal caruncle of the human eye. 



The specimens examined were from Georgia,and kindly sent to me by Dr. Lewis 

 and Mr. N. A. Pratt, Jr. 



Unio Boykinianus, Lea. Trans. Anier. Phil. Soc, vol. viii. pi. 13, fig. 22. Obs. vol. iii. p. 46. 



Branchial uterus — none had charged uteri. Branchiae very large, inner ones much 

 the larger, very much curved below, free, the largest specimen near only to the pos- 

 terior end of abdominal sack, the smaller ones more than half the length of ab- 

 dominal sack. Palpi very long, pointed and united far down on the posterior edges. 

 Mantle thin, with a broad margin, dark bordered on the inner posterior edges. 

 Branchial opening very large, with numerous small, dark-brown papilla? on the inner 

 edges. Anal opening very large, with exceedingly minute, dark-brown papillae on 

 the inner edges. Super-anal opening large, with a brown line on the inner edges, not 

 united below. Color of the mass whitish. 



Remarks. — Taken in the Chattahoochee and Flint Eivers in May, 1855, and were 

 kindly sent to me by Bishop Elliott. 



Unio alatus, Say. Nicholson's Encyc, Am. ed., Article Conch., pi. 4. 



Branchial uterus occupies the posterior half of the outer branchia?. In this speci- 

 men there were about thirty ovisacks in each of the two leaves. Branchiae very 

 large, rounded below, inner ones much the larger, united the whole length of abdomi- 

 nal sack. Palpi rather small, subtriangular, attached nearly the whole length of 

 the posterior edges. Mantle thin, much thickened at the edges. Branchial opening 

 very large, with numerous small papilla? on the inner edges. Anal opening very 

 small, with very minute, dark papilla?. Super-anal opening very long, united for a 

 short distance below. Color of the mass whitish. 



Embryonic shell wedge-shape, clear white, has four small hook-like processes. See 

 Journ. Acad. Nat. Sci., vol. iv. pi. 5, fig. 25. Obs. vol. vi. p. 48. 



Buffalo, New York, Mr. A. T. Jackson. 



Unio nasutus, Say. Nicholson's Ency., Arner. Ed., Art. Conch., pi. 4, fig. 1. 



Branchial uterus occupies the whole length of the outer branchiae. Branchiae 

 rather large, inner ones somewhat the larger, free only at the extreme posterior end of 

 abdominal sack. Palpi small, subtriangular, thin, united for a short distance on the 

 posterior edges. Mantle thin, much thickened at the edges. Branchial open- 

 ing rather large, with numerous dark papilla? on the inner edges. Anal opening 



* See Journal Acad. Nat. Sci., vol. iv. pi. 29, fig. 102 and Obs. vol. vii. p. 39. 



