388 MURICIDiE. 



the wliorls margined by a sharp ridge, of a darker color; suture 

 profoundly impressed ; the ridge terminates abruptly before, in a 

 very short, twisted, wrinkled beak ; aperture small, about one sixth 

 tlie length of the shell ; outer lip scalloped when perfect. Length, 

 half an inch ; breadth, one eighth of an inch ; divergence, twenty- 

 two degrees. 



Obtained by Professor C. B. Adams, at Nantucket and in New 

 Bedford Harbor, by whom it was described and named in honor of 

 G. B. Emerson, Esq., President of the Boston Society of Natural 

 History. 



This prettily sculptured shell is distinguished by its short aper- 

 ture and beak, its broad base, from which the flattened whorls reg- 

 ularly taper to an acute apex ; and by the pretty strings of bead- 

 like granules encircling it. These beads are sometimes so worn 

 down as to present the appearance of a continuous line dilating at 

 regular intervals. 



This shell is unequivocally pronounced by Mi-. Sowerby to be the 

 Murex tubercularis of Montagu. But, after a careful examination 

 of all the descriptions of that shell, I am led to conclude, either that 

 I sent Mr. Sowerby a poor representation of our shell, or that he 

 would decide differently on a second, more careful inspection. No 

 author ascribes to M. tubercularis more than eight or ten volutions, 

 and one fourth of an inch for its length ; while ours has commonly 

 •twice that length, with sixteen or eighteen volutions. Montagu 

 says, in his " Supplement," "It has as an invariable character, three 

 series of tubercles of equal size, on each volntion." But at the or- 

 dinary length of M. tubercularis, our shell has but two series of 

 granules ; and when the third appears, it is very perceptibly smaller 

 than the other two series. On account of so decided a variation in 

 size and sculpture, I think it proper still to regard our shell as a 

 distinct species, trusting to future observations to settle the point 

 definitely. 



[Aninuil: foot somewhat long, truncate in front, palish with white 

 maculations ; neck flesh color in middle with white spots, a line of 

 white on each side continued from tentacles inside of eyes. Head 

 l)road, truncate-rounded, dark flesh-color in front edge. Sole with 

 white l»lotch in middle. Foot very small, notched posteriorly. 

 QStimpson.^ 



