PRN ge ths He, Re EMT Mee Nee oy ee 
. 
* 
ett 
W. Stimpson on the so-called Melanians of N. America. 43 
water to the gills. The duct of the generative organ lies along 
the right side of the pallial cavity, in the angle formed by the 
cover any opening in either lamina at this point, so that the gen- 
erative products are probably discharged from the inner surfaces 
of, and between, the laminze, which conduct them like a channel 
toward the external element. The rectum lies in the usual posi- 
tion, parallel with and close above (to the right of) the genera- 
tive duct. The fieces are not voided in a continuous worm-like 
cylinder, as in many gasteropods, but the cylinder is divided 
transversely, in the rectum, into sausage-shaped sections. 
Branchie,—The gills, as in most other Ctenobranchiates, are 
two in number, lying upon the inner surface of the mantle. The 
principal or comb-like gill‘ is much elongated, extending to the 
* It is difficult to imagine > be what H. & A. Adams base their character of the 
he Melaniide,—“gill composed of rigid, cylindrical plates.” (Gen. of 
i, 293.) The italics are my own. 
