UNITED STATES. 41 



largest size of the shell of one taken by me near Cincinnati, is in broatUh 8, in length 

 54 and in diameter 3J inches. The two valves, without the soft parts, weighed 2 

 pounds, 9i ounces These dimensions ai'e greater than those of any specimens of 

 which I have any account. 



The figure is intended to represent the position of the branchial uterus as existing 

 in the four leaves of the branchioo. The two of the right side are prominent and give 

 a very correct idea of these masses. The right poZ/Jus lying on the abdominal mass is 

 also correctly displayed. The specimen having been some time in alcohol, did not 

 present the means of giving the ^rtp(7/re of the branchial opening in a natural state, 

 and this part will, therefore, be found to differ from the drawing, somewhat, in living 

 specimens. 



UiVIO STRAMIXEUS Con.* PI. 30, fig. lOG. 



Softx>arts. — Branddal uterus occupies the posterior end of the outer branchi;\j. Ova 

 were found in the ovarium, but none in the uterus, which, however, consisted, in the 

 (mly specimen before me, of thirteen small sacks on each side, protruding beyond the 

 edge of the branchio3 ; these sacks are blackish on the lower ends, which color is 

 caused by a hJach secretion within. Branchiai rather large, slightly curved below, 

 inner ones the larger, united the whole length of abdominal sack. Palpi rather large, 

 subelliptical, united halfway down the posterior edges. Mantle very thin, very white, 

 with a rather broad, somewhat thickened border. The inferior posterior edges, for a 

 short distance below the branchial opening, have very small whitish papilla^, over 

 which numerous small black spots are dispersed, the base of the papillas being defined 

 by a black line, at the upper end of which there is a small round black spot, like an 

 eye. Along the basal line the papillte are continued to the middle, growing smaller 

 as they approach this their terminal point. These papillte are remarkable, being 

 thickly set, perfectly white and look like rows of fishes' teeth. Branchial openimj 

 rather large, with numerous whitish, elongate papilla), enlarged at the base and 

 pointed at the termination. Anal opening very small, with numerous, thickly 

 set, whitish papilltc on the inner edges, which are more remote than usual 

 from the outer edges. Anibs small, crenulate on the edges and pointed. Super-anal 

 opening rather small, colored within and united below. Color of the mass unusually 

 white. 



liemarls. — I have had liut a single specimen to examine, but it is in remarka- 

 l)ly l^e condition, having a clean and perfect epidermis, with the posterior slope 

 covered by well defined capillary rays, and with rays on the beaks diverging from 

 the tips. It was sent to me by the kindness of Dr. Spillman, of Columbus, Mississippi. 



* Am. Jour. Sci., Vol. 25, pi. 1, fig. G. 

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