4 THE NAUTILUS. 



will immediately coil it.<elf up again. Thi.s cylinder is of subequal 

 diameter tliroaghout, and is as long as, and somewhat stouter than, 

 the cephalic tentacles. Externally, near its base, it is nearly smooth ; 

 further out, it is spirally striate; near its extremity, it becomes 

 thicker and rather deeply externally grooved longitudinally, with 

 short, even, close-set, slightly spiral, grooves. The opening at the 

 distal end is fringed with short, equal papillae, each one corresponding 

 to the thickened interspace between two of the grooves. These raised 

 folds, or interspaces, are also finely transversely striate. At the 

 base of the cylinder, the epipodium extends backward to the first 

 lateral filament ; and the margin of this part is perfectly entire and 

 simple, showing neither fringe nor granulation. The object of this 

 apparatus is self-evident. The cylinder serves as a conduit for the 

 seminal fluid ejected from the verge. Whether it may be employed 

 in an actual copulation is doubtful ; it may merely serve to spread 

 the seminal matter over the eggs as they are deposited by the female. 

 I am not aware that anything of this sort has been observed in any 

 other gastropod, up to the present time. 



The edge of the mantle is smooth, entire, and slightly thickened. 

 Within the nuchal chamber the anus is visible on the right side. 

 The end of the intestine, for a considerable distance, is free from the 

 mantle and projects like a tentacle. The termination is slightly con- 

 stricted, then enlarged into a cup, or trumpet-shaped ending, Avhich 

 nearly reaches the mantle-edge. 



The intestine itself, after leaving the stomach, is much convoluted, 

 but in the main, rises and is brought forward nearly to the mantle- 

 edge above the stomach ; then turns back and is carried far into the 

 visceral coil before it is again brought forward and terminated as 

 above described. The food consists of Foramiuifera. 



The gill is free, except at its base, and consists of very elongate- 

 triangular foundation, from which depend triangular lamellae, 

 without a raphe and wide at their bases. These grow larger prox- 

 imaliy. 



The operculum is thin, polished, amber-colored, centrally de- 

 pressed, having a central projection, or nipple, on its under-side, and 

 consists of about four whorls. 



The specimen affording the above notes has been identified with 

 Mr. Watson's type specimen, and is now deposited with it in the 

 British Museum. It was dredged by the U. S. Fish Commission 

 east of Chesapeake Bay, in 1685 fathoms. 



